CVE-2007-4321

Severity: medium (CVSS 6.8 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2007-08-14 · updated 2026-06-16

Description

fail2ban 0.8 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial of service by adding arbitrary IP addresses to the sshd log file, as demonstrated by logging in via ssh with a client protocol version identification containing an IP address string, a different vector than CVE-2006-6302.

Affected products

fail2ban: 0.8

References

http://bugs.gentoo.org/show_bug.cgi?id=181214
http://osvdb.org/42484
http://secunia.com/advisories/23237
http://secunia.com/advisories/28374
http://security.gentoo.org/glsa/glsa-200707-13.xml
http://www.debian.org/security/2008/dsa-1456
http://www.ossec.net/en/attacking-loganalysis.html
http://www.securityfocus.com/bid/25117
http://bugs.gentoo.org/show_bug.cgi?id=181214
http://osvdb.org/42484
http://secunia.com/advisories/23237
http://secunia.com/advisories/28374

Get alerted when CVE-2007-4321 or the next vulnerability affects your stack