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CERT Coordination Center

AOL Instant Messenger vulnerable to denial-of-service attack via buddy list transfers

Vulnerability Note VU#912659

Original Release Date: 2002-06-11 | Last Revised: 2002-06-19


America Online's Instant Messenger (AIM) contains a remotely exploitable buffer overflow vulnerability.


AOL Instant Messenger is a program for communicating with other users over the Internet and is widely used. During a buddy list transfer, a buffer overflow may occur. It has not been determined if this transfer happens via peer-to-peer, peer-to-server-to-peer, or both types of connections.


A denial-of-service situation is caused. It has not been determined if this vulnerability can lead to the remote execution of code.


Users can mitigate this vulnerability by upgrading AIM to version 4.8.2790 or higher. It is also reported that on March 14, 2002 AOL implemented server-side filtering to mitigate this vulnerability.

Block AIM Authentication at the Firewall

Blocking connections to on port 5190/tcp may prevent users on the local network from authenticating to the AIM server. This may be sufficient to prevent the vulnerability from being exploited.

Block Untrusted Messages

AIM permits the user to only accept messages from known peers. By enabling this feature, you may be able to prevent the vulnerability from being exploited. Note that you may still be vulnerable to attacks that originate from known peers if the vulnerability is exploited in a worm-like fashion.

Vendor Information


AOL Time Warner Affected

Notified:  March 04, 2002 Updated: June 13, 2002



Vendor Statement

Upgrade to AIM 4.8.2790 or higher.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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Our thanks to AOL Time Warner for their help in analyzing this vulnerability.

This document was written by Jason Rafail.

Other Information

CVE IDs: None
Severity Metric: 0.23
Date Public: 2002-03-01
Date First Published: 2002-06-11
Date Last Updated: 2002-06-19 15:00 UTC
Document Revision: 13

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