OTX Threat: PhantomCore and PhantomGraph backdoors delivered via an unpatched TrueConf server

The Head Mare APT group exploited a chain of vulnerabilities in TrueConf video conferencing servers to deploy PhantomCore and PhantomGraph backdoors. Attackers connected to unpatched TrueConf servers via port 4307/TCP without authorization, using vulnerabilities KLCERT-26-057 and KLCERT-26-058 to execute arbitrary code with NT AUTHORITY\SYSTEM privileges. They replaced legitimate TrueConf client i Sectors: Manufacturing, Electronics, Transportation