Fail2ban 0.8.9, Denial of Service (Apache rules only)

2013-06-11 / 2013-06-15

Credit: Krzysztof Katowicz-Kowalewski

Risk: Medium

Local: No

Remote: Yes

CVE: CVE-2013-2178

CWE: CWE-20

CVSS Base Score: 5/10

Impact Subscore: 2.9/10

Exploitability Subscore: 10/10

Exploit range: Remote

Attack complexity: Low

Authentication: No required

Confidentiality impact: None

Integrity impact: None

Availability impact: Partial

Version 0.8.9 (latest) of Fail2ban allows to perform remote denial of service for arbitrary chosen IP address. Address 
listed on Fail2ban's whitelist are not affected. The vulnerability exists in Apache rules and it is caused by improper 
validation of a log file by regular expression. Malicious user can easily inject his own data to analyzed logs and 
deceive monitoring engine.

Affected files:
/filter.d/apache-auth.conf
/filter.d/apache-nohome.conf
/filter.d/apache-noscript.conf
/filter.d/apache-overflows.conf

Time frames:
01.06.2013 - Cyril Jaquier (contact section) has been informed about the vulnerability (no response)
08.06.2013 - The vulnerability has been released to the public.

More information, including proof of concept and patches is available here:
https://vndh.net/note:fail2ban-089-denial-service

References:

https://vndh.net/note:fail2ban-089-denial-service

http://seclists.org/oss-sec/2013/q2/557

See this note in RAW Version

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Fail2ban 0.8.9, Denial of Service (Apache rules only)

References:

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