GLSA-200710-14 : DenyHosts: Denial of Service
Medium Nessus Plugin ID 27049
SynopsisThe remote Gentoo host is missing one or more security-related patches.
DescriptionThe remote host is affected by the vulnerability described in GLSA-200710-14 (DenyHosts: Denial of Service)
Daniel B. Cid discovered that DenyHosts used an incomplete regular expression to parse failed login attempts, a different issue than GLSA 200701-01.
A remote unauthenticated attacker can add arbitrary hosts into the blacklist, including the 'all' keyword, by submitting specially crafted version identification strings to the SSH server banner. An attacker may use this to prevent legitimate users from accessing a host remotely.
There is no known workaround at this time.
SolutionAll DenyHosts users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose '>=app-admin/denyhosts-2.6-r1'