More threat actors have started exploiting two recently resolved vulnerabilities in the ConnectWise ScreenConnect remote desktop access software.
The issues, tracked as CVE-2024-1709 (CVSS score of 10) and CVE-2024-1708 (CVSS score of 8.4), are described as an authentication bypass flaw and a path traversal bug.
ConnectWise disclosed the security defects on February 19, when it announced patches for them. Two days later, the company updated its advisory to warn of ongoing exploitation.
“Essentially, a bad actor could mimic the role as system admin, delete all other users and take over the instance,” the company notes in its advisory.
A proof-of-concept (PoC) exploit targeting the flaws, collectively referred to as SlashAndGrab, was made public last week, and threat actors quickly started exploiting them for malware delivery.
Now, Trend Micro says that more cybercrime groups have started exploiting the flaws, including the Black Basta and Bl00dy ransomware groups.
Following initial access to vulnerable servers, Black Basta was seen performing reconnaissance, discovery, and elevation of privilege activities, and deploying Cobalt Strike payloads.
In addition to searching for members of the ‘domain admin’ group, the attackers also added new accounts to the administrator group and deployed scripts to identify machines that recently connected to the Active Directory environment.
Other threat actors were also seen deploying Cobalt Strike payloads to the compromised servers, as well as attempting to disable Windows Defenders’ real-time monitoring functionality.
The Bl00dy ransomware group was seen exploiting ConnectWise ScreenConnect vulnerabilities in attacks deploying leaked builders from Conti and LockBit. The ransom notes deployed in both cases, however, identify the attackers as the Bl00dy group.
In other attacks, Trend Micro observed threat actors exploiting ScreenConnect flaws to deploy the XWorm malware, which provides remote access to the infected systems, can spread across networks, steal data, and fetch additional payloads.
Trend Micro also observed attacks where threat actors deployed other remote access software, including Atera and Syncro, as well as another instance of ConnectWise.
ConnectWise customers are advised to update to ScreenConnect version 23.9.8 as soon as possible.
“Following our detailed examination of various threat actors exploiting vulnerabilities in ConnectWise ScreenConnect, we emphasize the urgency of updating to the latest version of the software. Immediate patching is not just advisable; it is a critical security requirement to protect your systems from these identified threats,” Trend Micro notes.
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