Denial of Service Vulnerability in fail2ban by Bastille Technologies

CVE-2007-4321

What is CVE-2007-4321?

The fail2ban product, specifically versions 0.8 and earlier, contains a vulnerability that arises from improper parsing of sshd log files. This oversight enables remote attackers to inject arbitrary hosts into the /etc/hosts.deny file, potentially leading to a denial of service condition. Malicious users can exploit this flaw by logging in via SSH using a client protocol version that includes a malicious IP address string. As a result, attackers can manipulate access controls on the targeted system, disrupting service availability.

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