The Mail Fetch plugin in SquirrelMail 1.4.20 and earlier allows remote authenticated users to bypass firewall restrictions and use SquirrelMail as a proxy to scan internal networks via a modified POP3 port number.
conference.hitb.org/hitbsecconf2010dxb/materials/D1%20-%20Laurent%20Oudot%20-%20Improving%20the%20Stealthiness%20of%20Web%20Hacking.pdf#page=69
lists.apple.com/archives/security-announce/2012/Feb/msg00000.html
lists.fedoraproject.org/pipermail/package-announce/2010-June/043239.html
lists.fedoraproject.org/pipermail/package-announce/2010-June/043258.html
lists.fedoraproject.org/pipermail/package-announce/2010-June/043261.html
rhn.redhat.com/errata/RHSA-2012-0103.html
secunia.com/advisories/40307
squirrelmail.org/security/issue/2010-06-21
squirrelmail.svn.sourceforge.net/viewvc/squirrelmail/branches/SM-1_4-STABLE/squirrelmail/plugins/mail_fetch/functions.php?r1=13951&r2=13950&pathrev=13951
squirrelmail.svn.sourceforge.net/viewvc/squirrelmail/branches/SM-1_4-STABLE/squirrelmail/plugins/mail_fetch/options.php?r1=13951&r2=13950&pathrev=13951
support.apple.com/kb/HT5130
www.mandriva.com/security/advisories?name=MDVSA-2010:120
www.openwall.com/lists/oss-security/2010/05/25/3
www.openwall.com/lists/oss-security/2010/05/25/9
www.openwall.com/lists/oss-security/2010/06/21/1
www.securityfocus.com/bid/40291
www.securityfocus.com/bid/40307
www.vupen.com/english/advisories/2010/1535
www.vupen.com/english/advisories/2010/1536
www.vupen.com/english/advisories/2010/1554