DenyHosts 'regex.py' Remote Denial of Service Vulnerability

Bugtraq ID:	64478
Class:	Failure to Handle Exceptional Conditions
CVE:	CVE-2013-6890
Remote:	Yes
Local:	No
Published:	Dec 19 2013 12:00AM
Updated:	Apr 13 2015 10:07PM
Credit:	Helmut Grohne
Vulnerable:	Phil Schwartz DenyHosts 2.6 Gentoo Linux Debian Linux 6.0 sparc Debian Linux 6.0 s/390 Debian Linux 6.0 powerpc Debian Linux 6.0 mips Debian Linux 6.0 ia-64 Debian Linux 6.0 ia-32 Debian Linux 6.0 arm Debian Linux 6.0 amd64
Not Vulnerable:	Phil Schwartz DenyHosts 2.7

DenyHosts 'regex.py' Remote Denial of Service Vulnerability

DenyHosts is prone to a remote denial-of-service vulnerability.

Successfully exploiting this issue allows remote attackers to deny further SSH network access to arbitrary IP addresses, denying service to legitimate users.

DenyHosts 'regex.py' Remote Denial of Service Vulnerability

Attackers use standard SSH-client software to exploit this issue.

The following example data is available:

ssh -l 'Invalid user root from 123.123.123.123' 21.21.21.21

DenyHosts 'regex.py' Remote Denial of Service Vulnerability

Solution:
Updates are available. Please see the references or vendor advisory for more information.

DenyHosts 'regex.py' Remote Denial of Service Vulnerability

References:

• DenyHosts Home Page (Phil Schwartz)
  
• Re: [SECURITY] [DSA 2826-1] denyhosts security update (Helmut Grohne)
  
• DSA-2826-1 denyhosts -- Remote denial of ssh service (Debian)