CVE-2021-4189

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.

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.

Se ha encontrado un fallo en Python, concretamente en la biblioteca del cliente FTP (File Transfer Protocol) en modo PASV (pasivo). El problema radica en cómo el cliente FTP confía en el host a partir de la respuesta PASV por defecto. Este fallo permite a un atacante configurar un servidor FTP malicioso que puede engañar a los clientes FTP para que sean conectados a una dirección IP y un puerto determinados. Esta vulnerabilidad podría conllevar a que los clientes FTP escanearan los puertos, lo que de otro modo no habría sido posible.