A flaw was found in Python, specifically in the FTP (File Transfer Protocol) client library in PASV (passive) mode. The issue is how the FTP client trusts the host from the PASV response by default. This flaw allows an attacker to set up a malicious FTP server that can trick FTP clients into connecting back to a given IP address and port. This vulnerability could lead to FTP client scanning ports, which otherwise would not have been possible.
The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.
| Link | Tags |
|---|---|
| https://bugs.python.org/issue43285 | patch vendor advisory |
| https://python-security.readthedocs.io/vuln/ftplib-pasv.html | third party advisory patch |
| https://github.com/python/cpython/commit/0ab152c6b5d95caa2dc1a30fa96e10258b5f188e | third party advisory patch |
| https://security-tracker.debian.org/tracker/CVE-2021-4189 | third party advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2036020 | patch third party advisory issue tracking |
| https://access.redhat.com/security/cve/CVE-2021-4189 | third party advisory |
| https://security.netapp.com/advisory/ntap-20221104-0004/ | third party advisory |
| https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html | mailing list |
| https://lists.debian.org/debian-lts-announce/2023/06/msg00039.html | mailing list |