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.
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
| Link | Tags |
|---|---|
| https://github.com/proftpd/proftpd/commit/ecff21e0d0e84f35c299ef91d7fda088e516d4ed | issue tracking third party advisory patch |
| https://github.com/proftpd/proftpd/commit/f59593e6ff730b832dbe8754916cb5c821db579f | issue tracking third party advisory patch |
| http://bugs.proftpd.org/show_bug.cgi?id=4295 | issue tracking patch |
| http://www.securityfocus.com/bid/97409 | vdb entry third party advisory |
| https://github.com/proftpd/proftpd/pull/444/commits/349addc3be4fcdad9bd4ec01ad1ccd916c898ed8 | issue tracking third party advisory patch |
| http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00004.html | vendor advisory |
| http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00022.html | vendor advisory |
| http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00009.html | vendor advisory |