Black Basta and Bl00dy ransomware gangs exploit recent ConnectWise ScreenConnect bugs
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2024-1709 +1 in the same advisory: …1708 | Authentication Bypass in ConnectWise ScreenConnect Creates Rogue Admin Accounts ConnectWise ScreenConnect (ConnectWise Control), a widely used remote-access and remote-monitoring tool, contains an authentication bypass (CWE-288) in its management interface. An attacker needs only network access to the management interface to trigger the flaw, with no valid credentials or user interaction required. A successful attacker gains administrative control of the ScreenConnect server by creating a new administrator-level account, providing a foothold that has already been used in ransomware campaigns against downstream managed environments. Any organization running ConnectWise ScreenConnect is affected, especially managed service providers and IT teams whose management interface is reachable from the internet; the source data specifies affected products but no version ranges. Exploitation is confirmed and urgent: CISA added the flaw to the KEV on 2024-02-22 with known ransomware use, EPSS assigns a 100% probability of exploitation within 30 days, and ConnectWise warned that no patch was available at the time of disclosure. Do: Follow ConnectWise's instructions immediately: no patch existed at disclosure, so apply the vendor's mitigations or, per the CISA KEV required action, restrict internet exposure of the management interface or discontinue use until mitigations are available, then upgrade to the vendor's patched release as soon as it ships. Audit ScreenConnect servers for unexpectedly created administrator-level accounts and unusual remote sessions, which are the attack's artifacts. Prioritize any instance whose management interface is reachable from the internet, given confirmed in-the-wild exploitation and known ransomware use. | 10.0 group max | 100% | KEV ransomware PoC ×3 |
| masstens of thousands of internet-exposed ScreenConnect servers (on the order of 10,000-30,000 instances in public internet scans at disclosure), managing millions… |
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Pierluigi Paganini
February 27, 2024
New threat actors have started exploiting ConnectWise ScreenConnect vulnerabilities, including the Black Basta and Bl00dy ransomware gangs.
Multiple threat actors have started exploiting the recently disclosed vulnerabilities, tracked as CVE-2024-1709 (CVSS score of 10) and CVE-2024-1708 (CVSS score of 8.4), in the ConnectWise ScreenConnect software.
ConnectWise recently warned of the following two critical vulnerabilities in its ScreenConnect remote desktop access product:
- CVE-2024-1709 – CWE-288 Authentication bypass using an alternate path or channel (CVSS score 10)
- CVE-2024-1708 – CWE-22 Improper limitation of a pathname to a restricted directory (“path traversal”) (CVSS score 8.4)
Both vulnerabilities were reported on February 13, 2024, through the company vulnerability disclosure channel via the ConnectWise Trust Center. The company is not aware of attacks in the wild exploiting these vulnerabilities, however, due to the higher risk of being targeted by exploits, ConnectWise recommends installing updates as emergency changes within days.
The issues affect ScreenConnect 23.9.7 and prior, below is the remediation provided in the advisory:
Two days after the vendor addressed the two vulnerabilities, it also updated its advisory to confirm the ongoing exploitation of both issues.
Trend Micro researchers observed multiple threat actor groups that are exploiting vulnerabilities in ConnectWise ScreenConnect for different purposes, including ransomware deployment, and data exfiltration attacks.
Trend Micro confirmed that Black Basta and Bl00dy ransomware groups are actively exploiting both flaws and shared details about their attack chains.
Black Basta operators exploit the flaws to gain initial foothold on the vulnerable server, then they perform reconnaissance, discovery, and privilege escalation activities.
The gang was observed deploying the popular post-exploitation tool Cobalt Strike.
The attackers were observed searching for members of the ‘domain admin’ group to identify potential high-value targets for further attacks. Then the attackers also added new accounts to the local administrators group and deployed scripts to identify machines that connected to the Active Directory environment within the past 90 days. The attackers attempt to target these machines in further attacks or use them for lateral movement within the target network.
The Bl00dy ransomware group was also observed exploiting the two flaws in campaigns to deploy leaked builders from Conti and LockBit. The ransom notes deployed in the attacks allowed the researchers to link the attacks to the Bl00dy group.
The researchers also observed attacks where threat actors exploited these vulnerabilities in ScreenConnect via the XWorm malware. XWorm is a versatile malware that not only grants threat actors remote access capabilities, but also allows attackers to propagate through networks, exfiltrate sensitive data, and download additional payloads.
After establishing a presence on the susceptible ConnectWise server, we observed threat actors trying to execute PowerShell commands to download and run the XWORM malware.
Trend Micro also spotted threat actors deploying other remote access software, such as Atera and Syncro.
“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.” Trend Micro concludes. “Immediate patching is not just advisable; it is a critical security requirement to protect your systems from these identified threats.”
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(SecurityAffairs – hacking, ConnectWise ScreenConnect)
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