CVE-2019-19781

CVE-2019-19781, also known as the Citrix Directory Traversal Bug, is a significant software vulnerability that was discovered over two years ago. Despite its age, it remains a potent threat and even made the X-Force top 10 vulnerability list for 2021. This flaw in the design or implementation of the software allows actors to gain initial access typically by exploiting a public-facing networking device like Citrix Netscaler. Other devices susceptible to similar exploitation include F5 BIG-IP, Pulse Secure/Ivanti VPNs, and more recently, PanOS firewalls. The actor identified as Gold Melody has been linked to attacks exploiting this vulnerability among others. In addition to CVE-2019-19781, Gold Melody has been known to exploit security flaws in JBoss Messaging, Oracle WebLogic, GitLab, Citrix ShareFile Storage Zones Controller, Atlassian Confluence, ForgeRock AM, and Apache Log4j servers. Notably, this actor continues to exploit the Citrix Directory Traversal Bug and a Microsoft Exchange remote code execution flaw (CVE-2020-0688). Despite the discovery of CVE-2019-19781 being over two years old, it continues to be a substantial security concern. The persistent use of this vulnerability by malicious actors like Gold Melody underscores the importance of timely patching and updating of systems. Organizations must remain vigilant against such threats, ensuring their public-facing networking devices are secure and regularly updated to mitigate the risk of exploitation.