GLSA 200701-01: DenyHosts: Denial of Service
| Severity: | normal |
| Title: | DenyHosts: Denial of Service |
| Date: | 01/03/2007 |
| Bugs: | |
| ID: | 200701-01 |
Synopsis
DenyHosts does not correctly parse log entries, potentially causing a remote Denial of Service.Background
DenyHosts is designed to monitor SSH servers for repeated failed login attempts.
Affected packages
| Package | Vulnerable | Unaffected | Architecture(s) |
|---|---|---|---|
| app-admin/denyhosts | < 2.6 | >= 2.6 | All supported architectures |
Description
Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that DenyHosts used an incomplete regular expression to parse failed login attempts.
Impact
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.
Workaround
There is no known workaround at this time.
Resolution
All DenyHosts users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-admin/denyhosts-2.6"
References
Availability
This GLSA and any updates to it are available for viewing at the Gentoo Security Website:
Concerns?
Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.
License
Copyright 2010 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license.