Debian DSA-2826-1 : denyhosts - remote denial of ssh service

medium Nessus Plugin ID 71586

Synopsis

The remote Debian host is missing a security-related update.

Description

Helmut Grohne discovered that denyhosts, a tool preventing SSH brute-force attacks, could be used to perform remote denial of service against the SSH daemon. Incorrectly specified regular expressions used to detect brute-force attacks in authentication logs could be exploited by a malicious user to forge crafted login names in order to make denyhosts ban arbitrary IP addresses.

Solution

Upgrade the denyhosts packages.

For the oldstable distribution (squeeze), this problem has been fixed in version 2.6-7+deb6u2.

For the stable distribution (wheezy), this problem has been fixed in version 2.6-10+deb7u2.

See Also

https://packages.debian.org/source/squeeze/denyhosts

https://packages.debian.org/source/wheezy/denyhosts

https://www.debian.org/security/2013/dsa-2826

Plugin Details

Severity: Medium

ID: 71586

File Name: debian_DSA-2826.nasl

Version: 1.9

Type: local

Agent: unix

Published: 12/23/2013

Updated: 1/11/2021

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.2

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:denyhosts, cpe:/o:debian:debian_linux:6.0, cpe:/o:debian:debian_linux:7.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/22/2013

Reference Information

CVE: CVE-2013-6890

BID: 64478

DSA: 2826