Description
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP (ssh_sftpd module) allows Path Traversal. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:is_within_root/2. The SFTP server uses string prefix matching via lists:prefix/2 rather than proper path component validation when checking if a path is within the configured root directory. This allows authenticated users to access sibling directories that share a common name prefix with the configured root directory. For example, if root is set to /home/user1, paths like /home/user10 or /home/user1_backup would incorrectly be considered within the root. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to ssh from 3.0.1 until 5.5.1, 5.2.11.6 and 5.1.4.14.
Problem types
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Product status
3.0.1 (otp) before *
pkg:otp/ssh@3.0.1 (purl) before pkg:otp/ssh@*
17.0 (otp) before *
Any version before *
Credits
Luigino Camastra / Aisle Research
Jakub Witczak
Michał Wąsowski
References
github.com/...ng/otp/security/advisories/GHSA-4749-w85x-hw9h
www.erlang.org/doc/system/versions.html
github.com/...ommit/27688a824f753d4c16371dc70e88753fb410590b
github.com/...ommit/9e0ac85d3485e7898e0da88a14be0ee2310a3b28
github.com/...ommit/5ed603a1211b83b8be2d1fc06d3f3bf30c3c9759