title: Possible RCE vulnerability in mailing action using mailutils (mail-whois)
description: fail2ban is a daemon to ban hosts that cause multiple authentication errors. In versions 0.9.7 and prior, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action mail-whois. Command `mail` from mailutils package used in mail actions like `mail-whois` can execute command 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 MITM attack or by taking over a whois server. The issue is patched in versions 0.10.7 and 0.11.3. As a workaround, one may avoid the usage of action `mail-whois` or patch the vulnerability manually.
problem types: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
affected:
{
vendor: fail2ban
product: fail2ban
versions:
version: <= 0.9.7, status: affected
version: >= 0.10.0, <= 0.10.6, status: affected
version: >= 0.11.0, <= 0.11.2, status: affected
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
attackVector: NETWORK
attackComplexity: HIGH
privilegesRequired: NONE
userInteraction: REQUIRED
scope: CHANGED
confidentialityImpact: NONE
integrityImpact: HIGH
availabilityImpact: NONE
baseScore: 6.1
baseSeverity: MEDIUM
]