AIX FTP server may not properly timeout ephemeral data ports

ID VU:118125
Type cert
Reporter CERT
Modified 2005-07-07T00:00:00



The IBM AIX FTP server may be vulnerable to a denial-of-service condition when passive data ports are not closed properly.


IBM AIX includes an FTP server, ftpd, which allows files to be transferred between hosts with the FTP protocol. This server is vulnerable to a condition where an attacker may be able to utilize all available ephemeral ports on the system. When the ephemeral port range is exhausted, no more ports are available for the system to use for an indefinite period of time, resulting in a system-wide network-based denial of service. Additionally, the memory usage caused by the sockets in use by ftpd may also create a local denial of service condition by limiting system resources available to other processes. AIX 5.1, 5.2, and 5.3 are affected.


A remote, authenticated user may be able to limit system and network resources and cause a denial-of-service condition. If anonymous FTP access is allowed, anonymous users are considered to be authenticated and may cause the same denial-of-service conditions.


Apply An Update

Please contact IBM or your vendor for information on resolutions, workarounds, updates, and fixes.

Systems Affected

Vendor| Status| Date Notified| Date Updated
IBM| | -| 07 Jul 2005
If you are a vendor and your product is affected, let us know.

CVSS Metrics

Group | Score | Vector
Base | N/A | N/A
Temporal | N/A | N/A
Environmental | N/A | N/A


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Thanks to Matt Mello and IBM for reporting this vulnerability.

This document was written by Ken MacInnis.

Other Information

  • CVE IDs: Unknown
  • Date Public: 07 Jul 2005
  • Date First Published: 07 Jul 2005
  • Date Last Updated: 07 Jul 2005
  • Severity Metric: 1.77
  • Document Revision: 6