CVE-2023-24489

CVE-2023-24489 is an improper access control flaw (CWE-284), rated critical at CVSS 9.8, in the customer-managed Citrix Content Collaboration ShareFile storage zones controller. It can be triggered remotely over the network by an unauthenticated attacker with no privileges and no user interaction (AV:N/AC:L/PR:N/UI:N). A successful attack allows the attacker to remotely compromise the customer-managed storage zones controller — described in vendor-adjacent coverage as remote code execution — giving control of the server that stores and syncs that organization's ShareFile files. Only organizations that self-host customer-managed storage zones controllers are affected; the vendor-managed (cloud) ShareFile service is not listed as affected. The flaw is being actively exploited in the wild: CISA added it to the KEV catalog on 2023-08-16, EPSS assigns a 97.3% probability of exploitation within 30 days (100th percentile), and the vendor urged customers to shut down or take unpatched controllers offline; ransomware use is not yet confirmed.

What to do: Apply the fix specified in the Citrix/ShareFile security bulletin by upgrading every customer-managed storage zones controller to the vendor's patched release, and follow vendor guidance to shut down or take offline any controller that cannot be patched immediately. Check whether controllers are internet-exposed and hunt for signs of compromise (unexpected files, processes, or webshells on storage zones), since the flaw is in the KEV catalog and ransomware use has not been ruled out.