Input validation error in Fail2ban

1) Input validation error

EUVDB-ID: #VU42618

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2013-2178

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to perform service disruption.

The apache-auth.conf, apache-nohome.conf, apache-noscript.conf, and apache-overflows.conf files in Fail2ban before 0.8.10 do not properly validate log messages, which allows remote attackers to block arbitrary IP addresses via certain messages in a request.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Fail2ban: 0.1.0 - 0.8.8

External links

http://lists.opensuse.org/opensuse-updates/2014-03/msg00021.html
http://www.debian.org/security/2013/dsa-2708
http://www.openwall.com/lists/oss-security/2013/06/13/7
http://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A17338
http://raw.github.com/fail2ban/fail2ban/master/ChangeLog
http://vndh.net/note:fail2ban-089-denial-service

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.