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.
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Please contact IBM or your vendor for information on resolutions, workarounds, updates, and fixes.
Thanks to Matt Mello and IBM for reporting this vulnerability.
This document was written by Ken MacInnis.
|Date First Published:||2005-07-07|
|Date Last Updated:||2005-07-07 20:08 UTC|