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.
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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