2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm

SEI Report
By
Describes the PORT command in FTP protocol, gives examples, and discusses solutions.
Publisher

Software Engineering Institute

Abstract

In the past few years, there have been ongoing discussions about problems related to the PORT command in the FTP protocol. These problems are based on the misuse of the PORT command in the FTP protocol.

The example attacks in this tech tip demonstrate the core component of the vulnerability: the contents of the FTP PORT command are not trustworthy as they are under the control of a potential attacker.

Part of a Collection

CERT Tech Tips

Cite This SEI Report

Software Engineering Institute (2002, October 16). 2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm. Retrieved August 20, 2026, from https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/.

@techreport{Citekey_2002,
author={Software Engineering Institute},
title={2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm},
month={Oct},
year={2002},
institution={Software Engineering Institute, Carnegie Mellon University},
url={https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/},
note={Accessed: 2026-Aug-20}
}

Software Engineering Institute. "2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm." Software Engineering Institute, Carnegie Mellon University. Software Engineering Institute, October 16, 2002. https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/.

Software Engineering Institute, "2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm," Software Engineering Institute, Carnegie Mellon University. Software Engineering Institute, 16-Oct-2002 [Online]. Available: https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/. [Accessed: 20-Aug-2026].

Software Engineering Institute. "2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm." Software Engineering Institute, Carnegie Mellon University, Software Engineering Institute, 16 Oct. 2002. https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/. Accessed 20 Aug. 2026.

Software Engineering Institute. 2002 Tech Tip: Problems With The FTP PORT Command or Why You Don't Want Just Any Port in a Storm. Software Engineering Institute. 2002. https://www.sei.cmu.edu/library/2002-tech-tip-problems-with-the-ftp-port-command-or-why-you-dont-want-just-any-port-in-a-storm/