In the IPv4 PASV path, the FTP Client accepts whatever address was sent in the server's `227` reply. Validation only covers the parse and the non-zero values, thus a malicious server can name any address and direct the Client there.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0