The 3CX VoIP Desktop Application has been compromised to deliver malware via legitimate 3CX updates. Huntress has been investigating this incident and working to validate and assess the current supply chain threat to the security community.

On 02 February 2023, an alert triggered in a Huntress-protected environment. At first glance, the alert itself was fairly generic - a combination of certutil using the urlcache flag to retrieve a remote resource and follow-on scheduled task creation - but further analysis revealed a more interesting set of circumstances. By investigating the event in question and pursuing root cause analysis (RCA), Huntress was able to link this intrusion to a recently-announced vulnerability as well as to a long-running post-exploitation framework linked to prominent ransomware groups.