GLSA-200507-20 : Shorewall: Security policy bypass
High Nessus Plugin ID 19282
SynopsisThe remote Gentoo host is missing one or more security-related patches.
DescriptionThe remote host is affected by the vulnerability described in GLSA-200507-20 (Shorewall: Security policy bypass)
Shorewall fails to enforce security policies if configured with 'MACLIST_DISPOSITION' set to 'ACCEPT' or 'MACLIST_TTL' set to a value greater or equal to 0.
A client authenticated by MAC address filtering could bypass all security policies, possibly allowing him to gain access to restricted services. The default installation has MACLIST_DISPOSITION=REJECT and MACLIST_TTL=(blank) (equivalent to 0). This can be checked by looking at the settings in /etc/shorewall/shorewall.conf Workaround :
Set 'MACLIST_TTL' to '0' and 'MACLIST_DISPOSITION' to 'REJECT' in the Shorewall configuration file (usually /etc/shorewall/shorewall.conf).
SolutionAll Shorewall users should upgrade to the latest available version:
# emerge --sync # emerge --ask --oneshot --verbose net-firewall/shorewall