Attention, there is a new path traversal vulnerability (CVE-2019-19781) with a 9.8 severity rating that can allow unauthenticated threat actors to execute arbitrary code on several Citrix products. These products include application delivery controllers (ADC), Gateways, and SD-WAN WANOP. Citrix provided a patch timeline that lists the dates of various patches for their respective product counterparts – all patches are expected to be released by the end of January 2020.
The Hacker News’ Mohit Kumar wrote a great blog post detailing the above vulnerabilities, and highlighting the currently active attacks. Positive Technologies’ security researcher Mikhail Klyuchnikov was responsible for first identifying this vulnerability in late December 2019. His research article highlights the fact that the vulnerability only takes a minute to exploit, and affected more than 80,000 companies in more than 158 countries. The more recent article published by Mohit on January 20, 2020, claims that number has dropped to 15,000 companies.
At this point, if your company uses Citrix, immediately reference the patch timeline to get a better understanding of when to expect an update, and then apply it right away. The patches for ADC and Gateway versions 11.1 and 12.0 have already been released. All remaining releases are expected on January 24, 2020. Note that each product requires a separate update, which you can determine by looking at your current version. Remote code execution vulnerabilities are not to be taken lightly. Stay safe, folks.