Hackers have been leveraging a server-side request forgery (SSRF) vulnerability in Ivanti Connect Secure, Policy Secure, and ZTA gateways to introduce a new backdoor named DSLog onto susceptible devices. The flaw, identified as CVE-2024-21893, enables attackers to bypass authentication and gain unauthorized access to restricted resources within Ivanti gateways. Ivanti promptly disclosed the vulnerability on January 31, 2024, and provided security updates along with mitigation recommendations to mitigate the risk. However, despite these measures, threat monitoring services observed multiple attempts to exploit the vulnerability, emphasizing the critical importance of promptly applying the provided fixes to safeguard networks against potential intrusions.
Furthermore, a recent report by Orange Cyberdefense confirms successful exploitation of CVE-2024-21893 to implant the DSLog backdoor, granting threat actors remote execution capabilities on compromised Ivanti servers. This discovery underscores the severity of the vulnerability and highlights the need for immediate action to secure vulnerable systems. Orange researchers uncovered nearly 700 compromised Ivanti servers, indicating the widespread impact of the exploitation campaign.
The DSLog backdoor operates by injecting malicious code into the Ivanti device’s code base through SAML authentication requests containing encoded commands. These commands enable threat actors to execute various operations on compromised devices, such as outputting system information and attempting to secure read/write filesystem permissions. Despite efforts to conceal their activities by wiping ‘.access’ logs, the attackers’ actions have been detected, emphasizing the importance of continuous monitoring and vigilance in defending against cyber threats.
In response to the ongoing exploitation of the vulnerability, it is crucial for organizations utilizing Ivanti gateways to adhere to the latest recommendations provided by the vendor. This includes promptly applying security patches and implementing additional mitigations to thwart potential attacks. By proactively addressing these vulnerabilities, organizations can mitigate the risk of unauthorized access and protect sensitive data from falling into the hands of malicious actors.