Hackers Exploit FortiGate SSL-VPN Flaw to Breach Thai ISP and Deploy MeshCentral Backdoor
Threat actors exploited FortiOS SSL-VPN flaw CVE-2024-21762 to breach Thai ISP Triple T Broadband, gaining root-level persistence via MeshCentral agents.
Attackers exploited CVE-2024-21762, an out-of-bounds write enabling unauthenticated RCE in FortiOS SSL-VPN, against Triple T Broadband's FortiGate 60F at mail.3bb.co.th, launching a Node.js reverse shell via a ROP payload. Hunt.io uncovered the operation through an exposed staging directory at 92.63.180[.]133:8888 containing 298 files of exploits, credential-harvesting scripts, session cookies, and a device inventory. Post-compromise, the actors deployed MeshCentral agents (device group TH-3BB, C2 www.ayuthayatech.com) running as root, plus a hidden SUID backdoor at /usr/local/bin/.rc, and also targeted an internal Pentaho/Tomcat server with Ghostcat (CVE-2020-1938). A cleanup script removed logs, shell histories, and web shells while deliberately preserving the MeshCentral agent and SUID backdoor.
Hackers Exploit FortiGate SSL-VPN Vulnerability to Attack Broadband Provider
Exposed attacker staging server reveals intrusion of Thai broadband provider 3BB via actively exploited FortiGate SSL-VPN flaw CVE-2024-21762.
Hunt.io found an open directory on server 92.63.180[.]133 holding 298 files detailing an intrusion into Triple T Broadband's 3BB brand, starting from a FortiGate 60F SSL-VPN at mail.3bb.co[.]th:10443. The actor weaponized CVE-2024-21762 (CVSS 9.8, KEV-listed since February 2024) using heap spraying and a ROP chain to gain a reverse shell. Post-exploitation included MeshCentral root-level persistence via www.ayuthayatech[.]com, Dirty COW/PwnKit privilege escalation, credential harvesting, SSH spraying against 55+ internal addresses, and log-deleting cleanup scripts; a stolen OpenVPN certificate and key from Triple T's PKI may still be valid.