In August 2024, Athenian Tech (AT) uncovered a critical security risk during a routine digital‑risk assessment conducted for a European holding company. One of the organisation’s publicly exposed servers was found running OpenSSH 8.9p1 on Ubuntu — a version vulnerable to the high‑severity “regreSSHion” flaw (CVE‑2024‑6387). This vulnerability, caused by a race condition in sshd’s signal handler, allowed remote unauthenticated attackers to repeatedly trigger LoginGraceTime and potentially execute arbitrary code as root. If exploited, the flaw could have enabled a complete system takeover, deployment of persistent backdoors, data exfiltration, and lateral movement into the company’s wider IT infrastructure, posing material operational and financial risks.
AT’s threat‑intelligence platform, Prime, detected the exposed SSH service and fingerprinted it as directly susceptible to regreSSHion exploitation. To validate the real‑world risk, AT reproduced the exploit in a controlled demo environment, demonstrating how quickly an attacker could obtain full system access. The exposure was then correlated with global telemetry data, which indicated widespread internet scanning for this specific vulnerability. A detailed incident report was delivered to the client, outlining the risk, the exploitation pathway, and urgent remediation steps, including patching, firewall restrictions, SSH hardening, and updated monitoring rules.
Impact
AT’s early detection alerted the company before active exploitation occurred, but the mitigation and patching process remained the organisation’s responsibility.
