Plus, new details emerge on the Scattered Spider cybercrime network and ArcaneDoor.

Thursday, April 25, 2024 14:00

I wrote last week about the problems arising from the massive backlog of vulnerabilities at the U.S. National Vulnerability Database.  

Thousands of CVEs are still without analysis data, and the once-reliable database of every single vulnerability that’s disclosed and/or patched is now so far behind, it could take up to 100 days for the National Institute of Standards and Technology (NIST) to catch up, and that would be assuming no new vulnerabilities are disclosed during that period. 

While the U.S. government and NIST try to sort out a potential solution, and hopefully await more funding and restructuring, NIST says it’s hoping to launch a consortium to help either rebuild the NVD or create a replacement.  

Other security experts have floated the idea of other companies or organizations creating a brand-new solution of their own. The main problem with that is, what’s in it for them?  

What works about the NVD is that it’s funded by the U.S. government, so the money is always coming in to help fund the workforce and at least gives MITRE and the other private companies who contribute to the NVD motivation to keep working on it. 

To start up a whole new database of \*every\* CVE out there would take countless man-hours, and then what at the end? Would the company or person(s) who created it start charging for access? 

Several open-source solutions have_man-hours_ popped up over the past few weeks, such as “NVD Data Overrides,” which “is meant to provide additional data that is currently missing from NVD.” However, these types of volunteer projects still can’t assign CVSS scores, because only the NVD is authorized to hand out official NVD CVSS scores. 

This brings up another problem for private companies that may want to develop a solution: Do they want to play referee?  

Sometimes, when there’s a disagreement on how severe a vulnerability is and what severity score to assign it, the NVD will weigh in and provide their own, independently calculated CVSS score. Who really wants to be the “bad guy” to get between a massive tech company like Microsoft or Apple and a security researcher saying a vulnerability is a 9.5 out of 10 CVSS? 

I absolutely give major credit to any volunteers or open-source developers who are working on their own solutions for essentially nothing — but how long can we expect them to keep maintaining these databases? 

Unfortunately, I don’t have a great answer for this, either. I’m far from an expert on vulnerability management, nor do I have any connections to the federal government. But I do feel the onus is on the government to come up with a solution, and potentially provide incentives for companies and researchers to participate in this new proposed consortium because I don’t see the incentives there for the private sector to come up with their own solution.  

**The one big thing **

ArcaneDoor is a new campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Talos and Cisco PSIRT recently identified a previously unknown actor, now tracked as UAT4356 by Talos and STORM-1849 by the Microsoft Threat Intelligence Center. This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor. UAT4356 deployed two backdoors as components of this campaign, “Line Runner” and “Line Dancer,” which were used collectively to conduct malicious actions on-target, which included configuration modification, reconnaissance, network traffic capture/exfiltration and potentially lateral movement.   

**Why do I care? **

Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications. In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations — critical infrastructure entities that are likely strategic targets of interest for many foreign governments. As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective. 

**So now what? **

There are some known indicators of compromise that customers can look for if they suspect they may have been targeted in this campaign. First, organizations should look for any flows to/from ASA devices to any of the IP addresses present in the IOC list provided at the bottom of this blog. This is one indication that further investigation is necessary. Potential targets can also follow the steps detailed in the Cisco ASA Forensic Investigation Procedures for First Responders. When following these procedures, first responders should NOT attempt to collect a core dump or reboot the device if they believe that the device has been compromised, based on the lina memory region output. Talos also released some Snort signatures to detect the activity on the wire including access attempts. Snort Signatures 63139, 62949 and 45575 have been released to detect the implants or associated behaviors. 

**Top security headlines of the week **

**A previously known Windows print spooler bug is still being actively exploited, according to Microsoft.** The company’s threat research team recently disclosed that APT28, a well-known Russian state-sponsored actor, is exploiting the vulnerability to deliver a previously unknown malware called “GooseEgg.” Microsoft disclosed and patched CVE-2022-38028 in October 2022, but APT28 may have been exploiting it as far back as 2020. The actor’s exploitation involved modifying a JavaScript constraints file in the printer spooler and executing it with SYSTEM-level permissions. The new research prompted the U.S. Cybersecurity and Infrastructure Security Agency (CISA) to add CVE-2022-38028 to its Known Exploited Vulnerabilities (KEV) catalog. If installed, GooseEgg can load other applications with System-level permissions and allow the adversary to execute remote code on the targeted device or deploy other backdoors. Another set of print spooler vulnerabilities, called PrintNightmare, made headlines in July 2021, though no one reported active exploitation of that vulnerability at the time. (SC Magazine, Security Week) 

**A new investigation revealed how members of the group Scattered Spider are partnering with Russian state-sponsored actors to carry out ransomware attacks.** Scattered Spider is made up of younger individuals based out of the U.S., U.K. and Canada. They are primarily English speakers who have been blamed for several notable ransomware attacks, including one against MGM Casinos that disrupted operations at several casinos and hotels last year. The group specializes in social engineering, more recently using LinkedIn to steal employee information and use that to infiltrate corporate networks. Members, some as young as teenagers, are connecting over the dark web and online forums like Discord and use their advanced knowledge of Western civilization to provide crucial details to Russian actors. The “60 Minutes” investigation also included new details about The Community (aka “The Comm,” the online collection of hackers who like to brag about their recent cybercrimes, often through Telegram. (CBS News) 

**The U.S. government has re-upped a law that expands government surveillance by opening the door for private companies to partner with the government on these types of activities.** The controversial Foreign Intelligence Surveillance Act (FISA) was re-approved just hours after it lapsed. The White House and proponents in U.S. Congress argued that the powers granted in Section 702 of the FISA helps prevent the spread of terrorism and cyber attacks and that any lapse in those powers would harm the government’s ability to gather crucial intelligence. However, privacy advocates say that the FISA is an overreach, and provides too much power for private companies to potentially spy on consumers. The bill also includes a new definition of “electronic communications service provider,” which could allow the U.S. government to force Big Tech companies and telecommunications providers to hand over users’ data if requested. (NBC News, TechCrunch) 

**Can’t get enough Talos? **

*   Talos Takes Ep. #180: What are the dangers of enabling sideloading and third-party apps? 
*   Suspected CoralRaider continues to expand victimology using three information stealers 
*   Brute-force attacks surge worldwide, warns Cisco Talos    
*   Cisco Warns of Massive Surge in Password-Spraying Attacks on VPNs 
*   Rare Computer Virus Detected in Ukrainian Network, Confidential Document Potentially Compromised 

**Upcoming events where you can find Talos **

**CARO Workshop 2024** **(May 1 - 3)** 

_Arlington, Virginia_

> Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

**RSA** **(May 6 - 9)** 

_San Francisco, California_    

**Cisco Live** **(June 2 - 6)** 

_Las Vegas, Nevada_  

**Most prevalent malware files from Talos telemetry over the past week **

_This section will be on a brief hiatus while we work through some technical difficulties._ _Several open-source solutions have_

The private sector probably isn’t coming to save the NVD

Attacks by a previously unknown threat actor leveraged two bugs in firewall devices to install custom backdoors on several government networks globally.

Source: Znakki via Shutterstock

A state-sponsored threat actor has exploited two Cisco zero-day vulnerabilities in firewall devices to target the perimeter of government networks with two custom-built backdoors, in a global cyber-espionage campaign.

Dubbed "ArcaneDoor," the campaign by the previously unknown actor — which researchers from Cisco Talos track as UAT4356 — has targeted Cisco Adaptive Security Appliance (ASA) firewall devices of several Cisco customers since at least December 2023, Cisco Talos researchers revealed in a blog post.

While the actor's initial access vector remains unknown, once it occurs, UAT4356 used a "sophisticated attack chain" involving exploit of the two vulnerabilities — a denial-of-service flaw tracked as CVE-2024-20353 and a persistent local execution flaw tracked as CVE-2024-20359 that have since been patched — to implant malware and execute commands across a small set of Cisco customers. Cisco Talos also flagged a third flaw in ASA, CVE-2024-20358, that was not used in the ArcaneDoor campaign.

The researchers also found evidence that the actor has interest in and potentially will attack devices from Microsoft and other vendors, making it crucial that organizations ensure that all perimeter devices "are properly patched, logging to a central, secure location, and configured to have strong multifactor authentication (MFA)," Cisco Talos wrote in the post.

**Custom Backdoor Malware for Global Governments**

The first sign of suspicious activity in the campaign came in early 2024 when a customer reached out to Cisco's Product Security Incident Response Team (PSIRT) and Cisco Talos about security concerns with its ASA firewall devices.

A subsequent several-months-long investigation conducted by Cisco and intelligence partners uncovered threat actor-controlled infrastructure dating back to early November 2023. Most of the attacks — all of which targeted government networks globally —occurred between December and early January. There is also evidence that the actor — which Microsoft also is now tracking as STORM-1849 — was testing and developing its capability as early as last July.

The primary payloads of the campaign are two custom backdoors— "Line Dancer" and "Line Runner" — which were used together by UAT4356 to conduct malicious activities on the network, such as configuration and modification; reconnaissance; network traffic capture/exfiltration; and potentially lateral movement.  

Line Dancer is a memory-resident shellcode interpreter that enables adversaries to upload and execute arbitrary shellcode payloads. In the campaign, Cisco Talos observed the malware being used to execute various commands on an ASA device, including: disabling the syslog; running and exfiltrating the command show configuration; creating and exfiltrating packet captures; and executing commands present in the shellcode, among other activities.

Line Runner meanwhile is a persistence mechanism deployed on the ASA device using functionality related to a legacy capability that allowed for the pre-loading of VPN clients and plugins on the device during booting that can be exploited as CVE-2024-20359, according to Cisco Talos. In at least one case, the threat actor also abused CVE-2024-20353 to facilitate this process.

"The attackers were able to leverage this vulnerability to cause the target ASA device to reboot, triggering the unzipping and installing" of Line Runner, according to the researchers.

**Protect the Perimeter From Cyberattackers**

Perimeter devices, which sit at the edge between an organization's internal network and the Internet, "are the perfect intrusion point for espionage-focused campaigns," providing threat actors a way to gain a foothold to "directly pivot into an organization, reroute or modify traffic, and monitor network communications into the secure network, according to Cisco Talos.

Zero-days on these devices are an especially attractive attack surface on these devices, notes Andrew Costis, chapter lead of the Adversary Research Team at MITRE ATT&CK testing firm AttackIQ.

"We've seen time and time again critical zero and n-day vulnerabilities being exploited with all of the mainstream security appliances and software," he says, noting previous attacks on bugs in devices from Ivanti, Palo Alto Networks, and others.

The threat to these devices highlights the need for organizations to "routinely and promptly" patch them using up-to-date hardware and software versions and configurations, as well as maintain close security monitoring of them, according to Cisco Talos.

Organizations also should focus on post-compromise TTPs of threat actors and test known adversary behaviors as part of "a layered approach" to defensive network operations, Costis says.

**Detecting ArcaneDoor Cyberattack Activity**

Indicators of compromise (IoCs) that customers can look for if they suspect they may have been targeted by ArcaneDoor include any flows to/from ASA devices to any of the IP addresses present in the IOC list included in the blog.

Organizations also can issue the command "show memory region | include lina" to identify another IOC. "If the output indicates more than one executable memory region … especially if one of these memory sections is exactly 0x1000 bytes, then this is a sign of potential tampering," Cisco Talos wrote.  

And, Cisco provided two sets of steps that network administrators can take to identify and remove the ArcaneDoor persistence backdoor Line Runner on an ASA device once the patch is applied. The first is to conduct a review of the contents of disk0; if a new file (e.g., "client\_bundle\_install.zip" or any other unusual .zip file) appears on the disk, it means that Line Runner had been present but is no longer active due to the update.

Administrators also can follow a series of commands provided that will create an innocuous file with a .zip extension that will be read by the ASA at reboot. If it appears on disk0, it means that Line Runner likely was present on the device in question. Administrators can then delete the "client\_bundle\_install.zip" file to remove the backdoor.

If administrators find a newly created .zip file on their ASA devices, they should copy that file off the device and email \[email protected\] using a reference to CVE-2024-20359 and including the outputs of the "dir disk0:" and "show version" commands from the device, as well as the .zip file that they extracted.

**About the Author(s)**

Elizabeth Montalbano is a freelance writer, journalist, and therapeutic writing mentor with more than 25 years of professional experience. Her areas of expertise include technology, business, and culture. Elizabeth previously lived and worked as a full-time journalist in Phoenix, San Francisco, and New York City; she currently resides in a village on the southwest coast of Portugal. In her free time, she enjoys surfing, hiking with her dogs, traveling, playing music, yoga, and cooking.

Cisco Zero-Days Anchor 'ArcaneDoor' Cyber-Espionage Campaign

Within BEC attacks, adversaries will send phishing emails appearing to be from a known or reputable source making a valid request, such as updating payroll direct deposit information.

Thursday, April 25, 2024 08:00

Business email compromise (BEC) was the top threat observed by Cisco Talos Incident Response (Talos IR) in the first quarter of 2024, accounting for nearly half of engagements, which is more than double what was observed in the previous quarter.  

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, which accounted for 29 percent of engagements. The high number of BEC attacks likely played a significant role in valid accounts being the top attack vector this quarter. Weaknesses involving multi-factor authentication (MFA) were observed within nearly half of engagements this quarter, with the top observed weakness being users accepting unauthorized push notifications, occurring within 25 percent of engagements.  

There was a slight decrease in ransomware this quarter, accounting for 17 percent of engagements. Talos IR responded to new variants of Phobos and Akira ransomware for the first time this quarter. 

Manufacturing was the most targeted vertical this quarter, closely followed by education, a continuation from Q4 2024 where manufacturing and education were also two of the most targeted verticals. There was a 20 percent increase in manufacturing engagements from the previous quarter. 

The manufacturing sector faces unique challenges due to its inherently low tolerance for operational downtime. This quarter, Talos IR observed a wide range of threat activity targeting manufacturing organizations including financially motivated attacks, such as BEC and ransomware, and some brute force activity targeting virtual private network (VPN) infrastructure. The use of compromised credentials on valid accounts was the top observed attack vector within attacks targeting the manufacturing sector this quarter, which represents a change from the previous quarter when the top attack vector observed in these types of engagements was exploiting vulnerabilities in public-facing applications.   

**Watch discussion on the report's biggest trends**

**Surge in BEC **

Within BEC attacks, adversaries will send phishing emails appearing to be from a known or reputable source making a valid request, such as updating payroll direct deposit information. BEC attacks can have many motivations, often financially driven, aimed at tricking organizations into transferring funds or sensitive information to malicious actors.  

BEC offers adversaries the advantage of impersonating trusted contacts to facilitate internal spearphishing attacks that can bypass traditional external defenses and increase the likelihood of deception, widespread malware infections and data theft. 

In one engagement, adversaries performed a password-spraying attack and MFA exhaustion attacks against several employee accounts. There was a lack of proper MFA implementation across all the impacted accounts, leading to the adversaries gaining access to at least two accounts using single-factor authentication. The organization detected and disrupted the attack before adversaries could further their access or perform additional post-compromise activities.    

In another cluster of activity, several employees received spear-phishing emails that contained links that, when clicked, led to a redirection chain of web pages ultimately landing on a legitimate single sign-on (SSO) prompt that was pre-populated with each victim’s email address. The attack was unsuccessful because none of the employees interacted with the email, which was likely due to multiple red flags. For example, the email was unexpected and sent from an external email address, and there was small text within the email that referred to the email as a fax, which was all indicators of a phishing attempt. 

**Ransomware trends **

Ransomware accounted for 17 percent of engagements this quarter, an 11 percent decrease from the previous quarter. Talos IR observed new variants of Akira and Phobos ransomware for the first time this quarter. 

**Akira **

Talos IR responded to an Akira ransomware attack for the first time this quarter in an engagement where affiliates deployed the latest ESXi version, “Akira\_v2,” as well as a Windows-based variant of Akira named “Megazord.” These new Akira variants are written in the Rust programming language, which is a notable change from the previously used C++ and Crypto++ programming languages.  

Talos IR could not determine how initial access was gained, which is common because ransomware attacks often involve multi-stage attack strategies that add additional complexity during the investigation process. Once inside the network, the adversaries began collecting credentials from the memory of the Local Security Authority Subsystem Service (LSASS) and the New Technology Directory Services Directory Information Tree (NTDS.dit) database, where Active Directory data is stored, and leveraged Remote Desktop Protocol (RDP) for lateral movement. Prior to encryption, Megazord ransomware began executing several commands to disable tools and impair defenses, including “net stop” and “taskkill.” Akira\_v2 appended the file extension “.akiranew” during encryption, while Megazord ransomware appended the file extension “.powerranges”.   

First discovered in early 2023, Akira operates as a ransomware-as-a-service (RaaS) model and employs a double extortion scheme that involves exfiltrating data before encryption. Akira affiliates are known to heavily target small- to medium-sized businesses within several verticals primarily located within the U.S. but have targeted organizations within the U.K., Canada, Iceland, Australia and South Korea. Akira affiliates are notorious for leveraging compromised credentials and exploiting vulnerabilities as a means of gaining initial access, such as the SQL injection vulnerability, tracked as CVE-2021-27876, affecting certain versions of Zoho ManageEngine ADSelfService Plus, and the vulnerability, tracked as CVE-2023-27532, affecting certain versions of Veeam’s Backup & Replication (VBS) software.    

**Phobos **

Talos IR has previously observed variants of Phobos ransomware, such as “Faust,” but this quarter, Talos IR responded to an engagement with the “BackMyData” variant of Phobos ransomware. The adversaries leveraged Mimikatz to dump credentials from Active Directory. The adversary also installed several tools in the NirSoft product suite designed to recover passwords, such as PasswordFox and ChromePass, for additional credential enumeration. 

The adversaries used PsExec to access the domain controller before setting a registry key to permit remote desktop connections. Shortly after, the adversaries also modified the firewall to allow remote desktop connections using the Windows scripting utility, netsh. The remote access tool AnyDesk was downloaded to enable remote access as a means of persistence in the environment. Talos IR assessed with high confidence that Windows Secure Copy (WinSCP) and Secure Shell (SSH) were likely used to exfiltrate staged data. Adversaries also relied on PsExec to execute commands, such as deleting volume shadow copies, as a precursor to deploying the ransomware executable. After encryption, the ransomware appended the file extension “.fastbackdata”.   

A notable finding was the persistent use of the “Users/\[username\]/Music” directory as a staging area for data exfiltration to host malicious scripts, tools and malware, a common technique used by numerous ransomware affiliates to evade detection and remain persistent in the environment. Talos IR also identified a digitally signed executable, “HRSword,” developed by Beijing Huorong Network Technology. It is a tool the affiliate used during the attack for potential secure file deletion and as a defensive measure to disable endpoint protection tools, which Phobos affiliates were previously using, according to public reporting.   

Phobos ransomware first emerged in late 2018 and shared many similarities with the Crysis and Dharma ransomware families. Unlike other ransomware families, there are many variants of Phobos ransomware, such as Eking, Eight, Elbie, Devos and Faust. There is little information known about the business model leveraged by the Phobos ransomware operation. In November 2023, Cisco Talos analyzed over a thousand samples of Phobos ransomware to learn more about the affiliate structure and activity, which revealed that Phobos may operate a RaaS model due to the hundreds of contact emails and IDs associated with Phobos campaigns, indicating the malware has a dispersed affiliate base. Talos assessed with moderate confidence that the Phobos ransomware operation is actively managed by a central authority, as there is only one private key capable of decryption in all observed campaigns. 

**Other observed threats  **

Talos IR responded to an attack where adversaries were attempting to brute force several Cisco Adaptive Security Appliances (ASAs). Although the adversaries were unsuccessful in their attack, this activity is in line with the recently observed trend affecting VPN services. 

Cisco Talos has recently seen an increase in malicious activity targeting VPN services, web application authentication interfaces, and Secure Shell (SSH) globally. Since at least March 18, Cisco has observed scanning and brute force activity sourcing from The Onion Router (TOR) exit nodes and other anonymous tunnels and proxies. 

Depending on the target environment, a successful attack could result in unauthorized access to a target network, possibly leading to account lockouts and denial-of-service (DoS) conditions. The brute force attempts include a combination of generic usernames and valid usernames unique to specific organizations. The activity seems indiscriminate and has been observed across multiple industry verticals and geographic regions. 

**Initial vectors **

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, accounting for 29 percent of engagements, a continuation of a trend from the previous quarter when valid accounts were also a top attack vector. 

**Security weaknesses **

For the first time, users accepting unauthorized MFA push notifications was the top observed security weakness, accounting for 25 percent of engagements this quarter. The lack of proper MFA implementation closely followed, accounting for 21 percent of engagements, a 44 percent decrease from the previous quarter. 

Users must have a clear understanding of the appropriate business response protocols when their devices are overwhelmed with an excessive volume of push notifications. Talos IR recommends organizations educate their employees about the specific channels and points of contact for reporting these incidents. Prompt and accurate reporting enables security teams to quickly identify the nature of the issue and implement the necessary measures to address the situation effectively. Organizations should also consider implementing number-matching in MFA applications to provide an additional layer of security to prevent users from accepting malicious MFA push notifications. 

Talos IR recommends implementing MFA on all critical services including all remote access and identity access management (IAM) services. MFA will be the most effective method for the prevention of remote-based compromises. It also prevents lateral movement by requiring all administrative users to provide a second form of authentication. Organizations can set up alerting for single-factor authentication to quickly identify potential gaps. 

**Top observed MITRE ATT&CK techniques **

The table below represents the MITRE ATT&CK techniques observed in this quarter’s IR engagements and includes relevant examples and the number of times seen. Given that some techniques can fall under multiple tactics, we grouped them under the most relevant tactic based on the way they were leveraged. Please note, this is not an exhaustive list. 

Key findings from the MITRE ATT&CK framework include:  

*   Remote access software, such as SplashTop and AnyDesk, were used in 17 percent of engagements this quarter, a 20 percent decrease from the previous quarter.  
*   The use of email hiding rules was the top observed defense evasion technique, accounting for 21 percent of engagements this quarter.   
*   Scheduled tasks were leveraged by adversaries the most this quarter for persistence, accounting for 17 percent of engagements this quarter, a 33 percent increase from the previous quarter.  
*   The abuse of remote services, such as RDP, SSH, SMB and WinRM, more than doubled this quarter compared to the previous quarter, accounting for nearly 60 percent of engagements. 

Reconnaissance 

Example 

T1589.001 Gather Victim Identity Information: Credentials 

Adversaries may gather credentials that can be used during their attack.  

T1598.003 Phishing for Information: Spearphishing Link 

Adversaries may send a spearphishing email with a link to a credential harvesting page to collect credentials for their attack. 

Resource Development 

Example 

T1586.002 Compromise Accounts: Email Accounts 

Adversaries may compromise email accounts that can be used during their attack for malicious activities, such as internal spearphishing. 

T1583.001 Acquire Infrastructure: Domains 

Adversaries may acquire domains that can be used for malicious activities, such as hosting malware. 

T1608.001 Stage Capabilities: Upload Malware 

Adversaries may upload malware to compromised domains to make it accessible during their attack.  

T1583.008 Acquire Infrastructure: Malvertising 

Adversaries may purchase online advertisements, such as Google ads, that can be used distribute malware to victims. 

T1608.004 Stage Capabilities: Drive-by Target 

Adversaries may prepare a website for drive-by compromise by inserting malicious JavaScript.  

Initial Access 

Example 

T1078 Valid Accounts 

Adversaries may use compromised credentials to access valid accounts during their attack. 

T1566 Phishing 

Adversaries may send phishing messages to gain access to target systems. 

T1189 Drive-by Compromise 

Victims may infect their systems with malware over browsing, providing an adversary with access.  

T1190 Exploit in Public-Facing Application 

Adversaries may exploit a vulnerability to gain access to a target system. 

T1566.002 Phishing: Spearphishing Link 

Adversaries may send phishing emails with malicious links to lure victims into installing malware.  

Execution 

Example 

T1059.001 Command and Scripting Interpreter: PowerShell 

Adversaries may abuse PowerShell to execute commands or scripts throughout their attack. 

T1059.003 Command and Scripting Interpreter: Windows Command Shell 

Adversaries may abuse Windows Command Shell to execute commands or scripts throughout their attack. 

T1569.002 System Services: Service Execution 

Adversaries may abuse Windows service control manager to execute commands or payloads during their attack. 

Persistence 

Example 

T1053.005 Scheduled Task / Job: Scheduled Task 

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for recurring execution of malware or malicious commands. 

T1574.002 Hijack Execution: DLL Side-Loading 

Adversaries may execute their own malicious code by side-loading DLL files into legitimate programs.  

Privilege Escalation 

Example 

T1548.002 Abuse Elevation Control Mechanism: Bypass User Account Control 

Adversaries may bypass UAC mechanisms to elevate their permissions on a system. 

Defense Evasion 

Example 

T1564.008 Hide Artifacts: Email Hiding Rules 

Adversaries may create inbox rules to forward certain incoming emails to a folder to hide them from the inbox owner. 

T1070.004 Indicator Removal: File Deletion 

Adversaries may delete files to cover their tracks during the attack.  

T1218.011 System Signed Binary Proxy Execution: Rundll32 

Adversaries may abuse the Windows utility rundll32.exe to execute malware.  

T1112 Modify Registry 

Adversaries may modify the registry to maintain persistence on a target system.  

T1562.010 Impair Defenses: Downgrade Attack 

Adversaries may downgrade a program, such as PowerShell, to a version that is vulnerable to exploits. 

Credential Access 

Example 

T1621 Multi-Factor Authentication Request Generation 

Adversaries may generate MFA push notifications causing an MFA exhaustion attack. 

T1003.005 OS Credential Dumping: NTDS 

Adversaries may dump the contents of the NTDS.dit file to access credentials that can be used for lateral movement. 

T1003.001 OS Credential Dumping: LSASS 

Adversaries may dump the contents of LSASS to access credentials that can be used for lateral movement 

T1003.002 OS Credential Dumping: Service Account Manager 

Adversaries may dump the contents of the service account manager to access credentials that can be used for lateral movement. 

T1110.002 Brute Force: Password Cracking 

Adversaries may use brute force account passwords to compromise accounts. 

Discovery 

Example 

T1069.001 Permission Groups Discovery: Local Groups 

Adversaries may attempt to discover local permissions groups with commands, such as “net localgroup.”  

T1069.002 Permission Groups Discovery: Domain Groups 

Adversaries may attempt to discover domain groups with commands, such as “net group /domain.” 

T1201 Password Policy Discovery 

Adversaries may attempt to discover information about the password policy within a compromised network with commands, such as “net accounts.” 

Lateral Movement 

Example 

T1021.001 Remote Services: Remote Desktop Protocol 

Adversaries may abuse valid accounts using RDP to move laterally in a target environment.  

T1534 Internal Spearphishing 

Adversaries may abuse a compromised email account to send internal spearphishing emails to move laterally. 

T1021.002 Remote Services: SMB / Windows Admin Shares 

Adversaries may abuse valid accounts using SMB to move laterally in a target environment. 

T1021.004 Remote Services: SSH 

Adversaries may abuse valid accounts using SSH to move laterally in a target environment. 

T1021.001 Remote Services: Windows Remote Management 

Adversaries may abuse valid accounts using WinRM to move laterally in a target environment. 

Collection 

Example 

T1114.002 Email Collection: Remote Email Collection 

Adversaries may target a Microsoft Exchange server to collect information.  

T1074.001 Data Staged: Local Data Staging 

Adversaries may stage collected data in preparation for exfiltration. 

T1074 Data Staged 

Adversaries may stage collected data in preparation for exfiltration. 

Command and Control 

Example 

T1105 Ingress Tool Transfer 

Adversaries may transfer tools from an external system to a compromised system. 

T1219 Remote Access Software  

Adversaries may abuse remote access software, such as AnyDesk, to establish an interactive C2 channel during their attack.  

Exfiltration 

Example 

T1567.002 Exfiltration Over Web Service: Exfiltration to Cloud Storage 

Adversaries may exfiltrate data to a cloud storage provider, such as Dropbox.  

Impact 

Example 

T1486 Data Encrypted for Impact 

Adversaries may use ransomware to encrypt data on a target system.  

T1490 Inhibit System Recovery 

Adversaries may disable system recovery features, such as volume shadow copies.  

T1657 Financial Theft 

Adversaries may commit financial fraud during the attack.

Talos IR trends: BEC attacks surge, while weaknesses in MFA persist

A new malware campaign leveraged two zero-day flaws in Cisco networking gear to deliver custom malware and facilitate covert data collection on target environments.
Cisco Talos, which dubbed the activity ArcaneDoor, attributing it as the handiwork of a previously undocumented sophisticated state-sponsored actor it tracks under the name UAT4356 (aka Storm-1849 by Microsoft).
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State-Sponsored Hackers Exploit Two Cisco Zero-Day Vulnerabilities for Espionage

Sources suspect China is behind the targeted exploitation of two zero-day vulnerabilities in Cisco’s security appliances.

Network security appliances like firewalls are meant to keep hackers out. Instead, digital intruders are increasingly targeting them as the weak link that lets them pillage the very systems those devices are meant to protect. In the case of one hacking campaign over recent months, Cisco is now revealing that its firewalls served as beachheads for sophisticated hackers penetrating multiple government networks around the world.

On Wednesday, Cisco warned that its so-called Adaptive Security Appliances—devices that integrate a firewall and VPN with other security features—had been targeted by state-sponsored spies who exploited two zero-day vulnerabilities in the networking giant's gear to compromise government targets globally in a hacking campaign it's calling ArcaneDoor.

The hackers behind the intrusions, which Cisco's security division Talos is calling UAT4356 and which Microsoft researchers who contributed to the investigation have named STORM-1849, couldn't be clearly tied to any previous intrusion incidents the companies had tracked. Based on the group's espionage focus and sophistication, however, Cisco says the hacking appeared to be state-sponsored.

“This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor,” a blog post from Cisco's Talos researchers reads.

Cisco declined to say which country it believed to be responsible for the intrusions, but sources familiar with the investigation tell WIRED the campaign appears to be aligned with China's state interests.

Cisco says the hacking campaign began as early as November 2023, with the majority of intrusions taking place between December and early January of this year, when it learned of the first victim. “The investigation that followed identified additional victims, all of which involved government networks globally,” the company's report reads.

In those intrusions, the hackers exploited two newly discovered vulnerabilities in Cisco's ASA products. One, which it's calling Line Dancer, let the hackers run their own malicious code in the memory of the network appliances, allowing them to issue commands to the devices, including the ability to spy on network traffic and steal data. A second vulnerability, which Cisco is calling Line Runner, would allow the hackers' malware to maintain its access to the target devices even when they were rebooted or updated. It's not yet clear if the vulnerabilities served as the initial access points to the victim networks, or how the hackers might have otherwise gained access before exploiting the Cisco appliances.

Cisco has released software updates to patch both vulnerabilities, and advises that customers implement them immediately, along with other recommendations for detecting whether they've been targeted. Despite the hackers' Line Runner persistence mechanism, a separate advisory from the UK's National Cybersecurity Center notes that physically unplugging an ASA device does disrupt the hackers' access. “A hard reboot by pulling the power plug from the Cisco ASA has been confirmed to prevent Line Runner from re-installing itself,” the advisory reads.

The ArcaneDoor hacking campaign represents just the latest series of intrusions to target network perimeter applications sometimes referred to as “edge” devices like email servers, firewalls, and VPNs—often devices intended to provide security—whose vulnerabilities allowed hackers to obtain a staging point inside a victim's network. Cisco's Talos researchers warn of that broader trend in their report, referring to highly sensitive networks that they've seen targeted via edge devices in recent years. “Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications,” they write. “In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations—critical infrastructure entities that are likely strategic targets of interest for many foreign governments.”

State-sponsored hackers' shift to compromising edge devices has become prevalent enough over the past year that Google-owned security firm Mandiant also highlighted it in its annual M-Trends report earlier this week, based on the company's threat intelligence and incident response findings. The report points to widely exploited vulnerabilities in network edge devices sold by Barracuda and Ivanti and notes that hackers—and specifically espionage-focused Chinese groups—are building custom malware for edge devices, in part because many networks have little or no way to monitor for compromise of the devices. Detecting the ArcaneDoor hackers' access to Cisco ASA appliances, in particular, is “incredibly difficult,” according to the advisory from the UK's NCSC.

Mandiant notes that it has observed Russian state-sponsored hackers targeting edge devices too: It's observed the unit of Russia's GRU military intelligence agency, known as Sandworm, repeatedly hack edge devices used by Ukrainian organizations to gain and maintain access to those victim networks, often for data-destroying cyberattacks. In some cases, the lack of visibility and monitoring in those edge devices has meant that Sandworm was able to wipe a victim network while holding on to its control of an edge device—then hit the same network again.

“They’re systemically targeting security appliances that sit on the edge for access to the rest of the network,” says John Hultquist, Mandiant's head of threat intelligence. “This is no longer an emerging trend. It's established."

Hultquist notes, however, that China is unmatched in its discovery and use of network appliance zero days, like the ones it has used to run rampant through Cisco firewalls over the past several months. He expects more to come, as China's cyberspies continue to turn devices meant to protect target networks against their owners. “It's unlikely these zero days are being produced haphazardly. We suspect a well-resourced, coordinated effort is underway to find and exploit these vulnerabilities,” Hultquist says. “Unfortunately, we'll almost certainly see several more zero-days in security appliances this year.”

'ArcaneDoor' Cyberspies Hacked Cisco Firewalls to Access Government Networks

ArcaneDoor is a campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Coveted by these actors, perimeter network devices are the perfect intrusion point for espionage-focused campaigns.

ArcaneDoor - New espionage-focused campaign found targeting perimeter network devices

An exploit for the vulnerability allows unauthenticated attackers to escape a virtual file system sandbox to download system files and potentially achieve RCE.

Source: Andre Boukreev via Shutterstock

Virtual file transfer system provider CrushFTP and various security researchers are sounding the alarm about a sandbox escape flaw in the CrushFTP server that attackers already have exploited as a zero-day in attacks against organizations in the US.

CrushFTP is a multiprotocol, multiplatform, cloud-based file transfer server. The security vulnerability, tracked as CVE-2024-4040, is an improper input validation bug in the CrushFTP file transfer server version 11.1. The company unveiled and patched the flaw on April 19 with the release of version 11.1.0 of the product; however, there already were various reports of threat actors hammering the flaw with an existing exploit.

These attacks, which were potentially "politically motivated," were targeted in nature for intelligence gathering and detected at various US entities, according to Crowdstrike's threat hunters Falcon OverWatch and Falcon Intelligence, which published an advisory on Reddit.

**A Developing Attack Scenario for Cloud File Transfer**

The attack scenario is developing, with new research by Tenable published April 23 identifying more than 7,100 CrushFTP servers publicly accessible "based on a Shodan query in a Nuclei template created by h4sh," according to the report. However, "it's unclear how many of these systems are potentially vulnerable," Satnam Narang, a Tenable senior staff research engineer, noted in the post.

Attacks are likely to continue on unpatched servers given that a proof-of-concept (PoC) exploit for the flaw is now publicly available, posted April 23 to GitHub by the researcher who discovered and reported the flaw to CrushFTP, Simon Garrelou of Airbus Community Emergency Response Team (CERT), Narang added.

Other attackers also aim to benefit from all the attention in the flaw, by targeting users with fake PoCs, Narang wrote, noting there already is a repository posted to GitHub that directs users to a third-party site called SatoshiDisk, which requests a payment of 0.00735 bitcoin (around $513) for an alleged exploit.

"It is unlikely that the exploit code will work and we do not expect it to be malicious in nature," Narang wrote. "Instead, it is more likely that the attackers are seeking to make money from the interest in the exploit code for this vulnerability."

**CVE-2024-4040: Potential for RCE**

The vulnerability as described by the vendor is an arbitrary read flaw that allows an attacker with low privileges to escape the server's virtual file system (VFS) sandbox to access and download system files.

However, there is evidence that it is more to the flaw than has so far been reported, Rapid7 researchers noted in a blog post published on April 23.

"Although the vulnerability has been formally described as an arbitrary file read, Rapid7 believes that it can be more accurately categorized as a server-side template injection (SSTI)," Caitlin Condon, Rapid7's director of vulnerability intelligence, wrote in the post.

CVE-2024-4040 is a "fully unauthenticated flaw" and is easy to exploit; successful exploitation allows not only or arbitrary file read as root, but also authentication bypass for administrator account access and full remote code execution (RCE), she observed.

"Successful exploitation allows a remote, unauthenticated attacker to access and potentially exfiltrate all files stored on the CrushFTP instance," Condon wrote.

**Exploit Code Available**

The PoC exploit posted by Garrelou includes two scripts. The first, scan\_host.py, attempts to use the vulnerability to read files outside the sandbox, according to the GitHub post.

"If it succeeds, the script writes Vulnerable to standard output and returns with exit code 1," according to Garrelou. "If exploiting the vulnerability does not succeed, the script writes Not vulnerable and exits with status code 0."

The second script, scan\_logs.py, looks for indicators of compromise in a CrushFTP server installation directory and, upon finding them, will attempt to extract the IP that tried to exploit the server.

**Patch Now for Full Protection**

The best way for organizations with CrushFTP present in their environment to mitigate the situation is to update their systems to the patched version of the product now, the company and security researchers alike advised.

Customers using a front-end demilitarized zone (DMZ) server to process protocols and connections in front of their main CrushFTP instance are afforded partial protection from exploit due to the protocol translation system used in the DMZ, according to CrushFTP.

"A DMZ, however, does not fully protect you, and you must update immediately," the company advised customers in its advisory. One of the factors complicating an organization's detection of exploitation of CVE-2024-4040 is that payloads "can be delivered in many different forms," Rapid7's Condon noted.

"When certain evasive techniques are leveraged, payloads will be redacted from logs and request history, and malicious requests will be difficult to discern from legitimate traffic," she wrote.

For this reason, Rapid7 recommends that CrushFTP customers harden their servers against administrator-level RCE attacks by enabling Limited Server mode with the most restrictive configuration possible. Condon added that they also should use firewalls wherever possible to aggressively restrict which IP addresses are permitted to access CrushFTP services.

**About the Author(s)**

Elizabeth Montalbano is a freelance writer, journalist, and therapeutic writing mentor with more than 25 years of professional experience. Her areas of expertise include technology, business, and culture. Elizabeth previously lived and worked as a full-time journalist in Phoenix, San Francisco, and New York City; she currently resides in a village on the southwest coast of Portugal. In her free time, she enjoys surfing, hiking with her dogs, traveling, playing music, yoga, and cooking.

Patch Now: CrushFTP Zero-Day Cloud Exploit Targets US Orgs

The US Senate has approved a bill that will ban TikTok, unless it finds a new owner, bringing it one step closer to being signed into law.

The US Senate has approved a bill that would effectively ban TikTok from the US unless Chinese owner ByteDance gives up its share of the immensely popular app.

Social video platform TikTok has experienced explosive growth since it first appeared in 2017, and is now said to have well over 1.5 billion users, with an estimated 170 million of them in the US.

Essentially, the bill says that TikTok has to find a new owner that is not based in a foreign adversarial country within the next 180 days or face a ban until it does comply. President Biden has committed to sign it into law as soon as it reaches his desk.

Since 2020, several governments and organizations have banned, or considered banning, TikTok from their staff’s devices, but a complete ban of an internet app would be a first in the US.

For a long time now, TikTok has been battling to convince politicians that it operates independently of ByteDance, which allegedly has deep ties to the Chinese Communist Party (CCP). For example, TikTok has repeatedly claimed the Chinese government has never demanded access to US data and that TikTok would not comply if it did.

While ByteDance denies any direct links to the Chinese Communist Party, a former executive at TikTok’s parent company claimed in court documents that the CCP had access to TikTok data, despite US storage of the data. The allegations came up in a wrongful dismissal lawsuit filed in May of 2023 in the San Francisco Superior Court.

The Electronic Frontier Foundation (EFF), an international non-profit digital rights group based in the US, says it opposes this bill, mainly because it is afraid that TikTok will not be the last app to face this type of ban.

TikTok also encouraged its users and creators to express their opposition to the bill. Last week, the social media company said the bill would:

> “Trample the free speech rights of 170 million Americans, devastate seven million businesses, and shutter a platform that contributes $24 billion to the US economy, annually.”

Chinese officials reportedly said the government would “firmly oppose” any forced sale of TikTok because it would “seriously undermine the confidence of investors from various countries, including China, to invest in the United States.”

Malwarebytes has a new free tool for you to check how much of your personal data has been exposed online. Submit your email address (it’s best to give the one you most frequently use) to our free Digital Footprint scan and we’ll give you a report and recommendations.

 TikTok comes one step closer to a US ban 

A new ongoing malware campaign has been observed distributing three different stealers, such as CryptBot, LummaC2, and Rhadamanthys hosted on Content Delivery Network (CDN) cache domains since at least February 2024.
Cisco Talos has attributed the activity with moderate confidence to a threat actor tracked as CoralRaider, a suspected Vietnamese-origin

CoralRaider Malware Campaign Exploits CDN Cache to Spread Info-Stealers

The infamous Russian threat actor has created a custom tool called GooseEgg to exploit CVE-2022-38028 in cyber-espionage attacks against targets in Ukraine, Western Europe, and North America.

Source: Science Photo Library via Alamy Stock Photo

A well-known Russian advanced persistent threat (APT) group has been using a custom tool to exploit a bug that been around for several years in the Windows Print Spooler service to elevate privileges and steal credentials in numerous intelligence-gathering attacks around the globe. It also appears to be paving the way for further attacks.

Fancy Bear (aka APT28, Forest Blizzard, Pawn Storm, Sofacy Group, and Strontium) is linked to the Russian General Staff Main Intelligence Directorate. It has been using a tool called GooseEgg since at least June 2020 and possibly as early as April 2019 to exploit the CVE-2022-38028 vulnerability in Windows Print Spooler service, Microsoft Threat Intelligence revealed in a blog post on April 22.

Microsoft patched the flaw, which allows an attacker who successfully exploits it to gain SYSTEM privileges, in October 2022. Fancy Bear is using GooseEgg to modify a JavaScript constraints file and execute it with SYSTEM-level permissions.

"While a simple launcher application, GooseEgg is capable of spawning other applications specified at the command line with elevated permissions, allowing threat actors to support any follow-on objectives such as remote code execution, installing a backdoor, and moving laterally through compromised networks," according to the post.

Microsoft discovered Fancy Bear deploying GooseEgg in attacks against various Ukrainian, Western European, and North American government, nongovernmental, education, and transportation sector organizations.

Windows Print Spooler, a printer services technology, is a popular target for attackers, who tend to pounce on numerous flaws affecting the software that manages the printing process in Windows. The most well-known of these is two security vulnerabilities collectively called PrintNightmare that were discovered in late June 2021 and spawned a series of well-documented attacks.

**GooseEgg Malware Tailored for Windows Print Spooler**

That Fancy Bear targeted the service itself is not out of the ordinary, according to Microsoft; however, its use of the newly discovered GooseEgg to elevate privileges in these attacks is a novel threat activity for the group. GooseEgg is typically deployed with a batch script that invokes a corresponding GooseEgg executable and sets up persistence as a scheduled task.

The GooseEgg binary then takes one of four commands, each with different runpaths. "While the binary appears to launch a trivial given command, in fact the binary does this in a unique and sophisticated manner, likely to help conceal the activity," according to the post.

Two of the binary's commands trigger the exploit for the Print Spooler flaw and launch either a provided dynamic link library (DLL) or executable with elevated permissions, while another command tests the exploit and checks that it has succeeded.

The name of an embedded malicious DLL file launched by GooseEgg typically includes the phrase "wayzgoose," such as wayzgoose23.dll. That DLL as well as other components of the malware are deployed to one of several installation subdirectories created under the Windows directory C:\\ProgramData, according to Microsoft Threat Intelligence.

The exploit ultimately replaces the C: drive symbolic link in the object manager to point to the newly created directory, resulting in Print Spooler being redirected to the actor-controlled directory containing the copied driver packages when it attempts to load this registry: C:\\Windows\\System32\\DriverStore\\FileRepository\\pnms009.inf\_amd64\_a7412a554c9bc1fd\\MPDW-Constraints.js.

Eventually, the auxiliary DLL wayzgoose.dll file launches in the context of the PrintSpooler service with SYSTEM permissions as "a basic launcher application capable of spawning other applications" with the same permissions, according to the post.

**Keeping Fancy Bear Cyber Espionage at Bay**

Fancy Bear has a history of attacking known vulnerabilities, particularly in Microsoft products, to compromise targets for its nefarious activities — which primarily involve, but are not limited to, intelligence gathering. Last year, it mounted a flurry of cyber-espionage attacks against government agencies in NATO countries and organizations in the Middle East that exploited CVE-2023-23397, a zero-click vulnerability in Microsoft's Outlook email client.

While the group's most high-profile attack may be its ties to hacking aimed at running interference in the 2016 US presidential elections, the group has been most notably active of late in various attacks against Ukraine since Russia's war against the country began in February 2022.

The best way that organizations can protect themselves against attacks from the Russian APT is to apply patches for the vulnerable products that it targets. Microsoft recommended that users apply the CVE-2022-38028 security update to mitigate the GooseEgg threat against Windows Print Spooler; meanwhile, the Microsoft Defender Antivirus detects the specific Forest Blizzard capability as HackTool:Win64/GooseEgg.

Another way to mitigate the issue is to disable the Windows Print Spooler service domain controller operations, since it isn't required, according to Microsoft. To help identify domain controllers that have the Print Spooler service enabled, Microsoft Defender for Identity has a built-in security assessment that tracks the availability of Print Spooler services on domain controllers.

Greg Fitzgerald, co-founder at Sevco Security, notes that printer bugs are particularly difficult to remediate because printers are often under-inventoried.

“Security teams have become incredibly efficient at identifying and remediating CVEs, but increasingly it's these environmental vulnerabilities that create security gaps giving malicious actors access to data," Fitzgerald says. "These vulnerabilities are hiding in plain sight throughout IT environments, creating a landscape of threats that security teams can’t see, but are still accountable for. The unfortunate reality is that most organizations are unable to create an accurate IT asset inventory that reflects the entirety of their attack surface. This puts them at the mercy of attackers who know where to look for forgotten IT assets that contain exploitable vulnerabilities.”

**About the Author(s)**

Elizabeth Montalbano is a freelance writer, journalist, and therapeutic writing mentor with more than 25 years of professional experience. Her areas of expertise include technology, business, and culture. Elizabeth previously lived and worked as a full-time journalist in Phoenix, San Francisco, and New York City; she currently resides in a village on the southwest coast of Portugal. In her free time, she enjoys surfing, hiking with her dogs, traveling, playing music, yoga, and cooking.

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