| Description |
In fail2bain up to version 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action "mail-whois". The "mail" command from the mailutils package used in mail actions like "mail-whois" can execute arbitrary commands if unescaped sequences (`\n~`) are available in "foreign" input (for instance in whois output). To exploit the vulnerability, an attacker would need to insert malicious characters into the response sent by the whois server, either via a man-in-the-middle (MITM) attack or by taking over a whois server. |