CVE-2017-7418

ProFTPD before 1.3.5e and 1.3.6 before 1.3.6rc5 controls whether the home
directory of a user could contain a symbolic link through the
AllowChrootSymlinks configuration option, but checks only the last path
component when enforcing AllowChrootSymlinks. Attackers with local access
could bypass the AllowChrootSymlinks control by replacing a path component
(other than the last one) with a symbolic link. The threat model includes
an attacker who is not granted full filesystem access by a hosting
provider, but can reconfigure the home directory of an FTP user.

Bugs

• <http://bugs.proftpd.org/show_bug.cgi?id=4295&gt;
• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=859592&gt;