Nasty regreSSHion bug in OpenSSH puts roughly 700K Linux boxes at risk

Glibc-based Linux systems urged to update due to a critical flaw in sshd, potentially leading to remote code execution.

New Vulnerability in OpenSSH

Qualys reports 700,000 vulnerable internet-facing sshd instances, highlighting the severity of the regression vulnerability dubbed "regreSSHion."

Scope and Impact

The flaw, a regression of CVE-2006-5051, reappeared in OpenSSH 8.5p1, affecting systems running glibc and possibly enabling full system compromise.

Root Cause and History

Systems running OpenBSD are immune due to a security enhancement implemented in 2001, safeguarding against the vulnerability in syslog().

OpenBSD Exception

Exploitation involves a race condition in the SIGALRM handler, potentially allowing attackers to execute arbitrary code and evade security measures.

Technical Details

OpenSSH versions earlier than 4.4p1 and 8.5p1 to 9.8p1 are vulnerable unless patched for CVE-2006-5051 and CVE-2008-4109.

Patching Efforts

Organizations are advised to apply patches promptly, restrict SSH access, and monitor networks for exploit attempts to mitigate risk.

Mitigation Strategies

The Linux community is rallying to share information and resources to help affected users secure their systems.

Community Response

Ubuntu and NixOS have released updates, emphasizing the importance of checking for patches across Linux distributions.

Industry Responses