#VU41566 Link following in Fail2ban - CVE-2009-5023

Vulnerability identifier: #VU41566

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2009-5023

CWE-ID: CWE-59

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Fail2ban
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Fail2ban

Description

The vulnerability allows a remote non-authenticated attacker to manipulate data.

The (1) dshield.conf, (2) mail-buffered.conf, (3) mynetwatchman.conf, and (4) mynetwatchman.conf actions in action.d/ in Fail2ban before 0.8.5 allows local users to write to arbitrary files via a symlink attack on temporary files with predictable names, as demonstrated by /tmp/fail2ban-mail.txt.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Fail2ban: 0.1.0 - 0.8.3

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External links
https://secunia.com/advisories/58841
https://security.gentoo.org/glsa/glsa-201406-03.xml
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=544232
https://github.com/fail2ban/fail2ban/blob/sdist/0.8.5/ChangeLog

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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