CVE-2023-4966

CVE-2023-4966, also known as "Citrix Bleed," is a critical zero-day vulnerability affecting Citrix Netscaler Gateway and Netscaler ADC products. Discovered in 2023, this flaw in software design or implementation allows sensitive information disclosure, with a high severity rating of 9.4 on the Common Vulnerability Scoring System (CVSS). The vulnerability enables attackers to bypass multifactor authentication through the use of stolen session tokens, making it an attractive target for threat actors due to its ease of exploitation. The vulnerability was exploited en masse months before Citrix published an advisory in October 2023. In one notable incident, the ransomware gangs targeted Ongoing Operations' Netscaler ADC and Netscaler Gateway products that had unpatched Citrix Bleed vulnerabilities. This exploit allowed attackers to gain remote access to organizations reliant on Citrix, leading to significant security breaches. One such breach affected Xfinity, a major American cable TV and internet service provider, resulting in a data breach impacting nearly 36 million people. The breach was attributed to the Citrix Bleed vulnerability, demonstrating the potential scale and impact of such exploits. Despite the availability of patches meant to mitigate this issue, many organizations failed to implement them promptly, leading to widespread security incidents. Check Point IPS has since provided protection against this threat, highlighting the ongoing efforts to secure systems against such vulnerabilities.