Citrix Bleed

Citrix Bleed, officially tracked as CVE-2023-4966, is a severe vulnerability in the design and implementation of Citrix Netscaler Gateway and Netscaler ADC products. This flaw, which has a CVSS score of 9.4, allows for sensitive information disclosure, providing deep system-level access that facilitates sophisticated and difficult-to-detect intrusions. The vulnerability was exploited extensively by ransomware groups such as LockBit, Medusa, ALPHV (BlackCat), and others, leading to numerous compromises in November 2023. The exploitation of Citrix Bleed by these ransomware groups resulted in significant breaches across various sectors. One high-profile target was aerospace giant Boeing, which suffered a disruptive breach attributed to the exploitation of Citrix Bleed. Other notable targets included companies like Allen & Overy. These groups leveraged a zero-day exploit for the Citrix Bleed vulnerability, gaining initial access to the targeted networks and establishing persistence while pivoting across these networks during their attacks. In response to the widespread exploitation of this vulnerability, security agencies have advised organizations to take certain countermeasures to reduce risk. Although specific attack vectors have not been disclosed, security researchers believe that the ransomware gangs may have exploited the Citrix Bleed vulnerabilities. Palo Alto Networks have also provided product protections for Citrix Bleed to help organizations mitigate the threat. Despite these measures, the vulnerability continues to be a significant concern, with new exploits being uncovered regularly.