DenyHosts: Denial of Service DenyHosts does not correctly parse log entries, potentially causing a remote Denial of Service. denyhosts January 03, 2007 January 03, 2007: 01 157163 remote 2.6 2.6

DenyHosts is designed to monitor SSH servers for repeated failed login attempts.

Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that DenyHosts used an incomplete regular expression to parse failed login attempts.

A remote unauthenticated attacker can add arbitrary hosts to the blacklist by attempting to login with a specially crafted username. An attacker may use this to prevent legitimate users from accessing a host remotely.

There is no known workaround at this time.

All DenyHosts users should upgrade to the latest version:

# emerge --sync # emerge --ask --oneshot --verbose ">=app-admin/denyhosts-2.6" CVE-2006-6301 taviso taviso