Bugtraq mailing list archives
AOL Instant Messenger DoS
From: Adam Spun <spunone () FAZED NET>
Date: Tue, 3 Oct 2000 13:56:25 -0500
AOL Instant Messenger version 4.1.2010 (others?) appears to be vulnerable to a DoS attack when handling file transfers with filenames containing %s. The problem I encountered is that trying to send a file to crash my victim's client would cause my client to crash first, defeating the purpose. To get around this, I got a copy of the Netscape/AOL Instant Messenger client available on Netscape's site which doesn't seem to be vulnerable to this bug. I created a file called %s%s%s%s%s%s%s%s%s%s.jpg and sent it as a file transfer to my victim, causing their client to crash immediately. There is an option in AIM to generate a warning before accepting messages or file transfers from people that aren't in your buddy list. Enabling this option did generate the warning, but did not stop the client from crashing. This is not my area of expertise, but this DoS is apparently related to a problem with format strings. I am unable to determine whether or not it is further exploitable beyond a simple DoS. -SpunOne http://www.FAZED.net Another interesting note is that creating a file named: %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s %s%s%s%s.jpg seems to do funny things to explorer.exe in WinME (explorer crashes) and Win98 when trying to view the properties of the file.
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- AOL Instant Messenger DoS Adam Spun (Oct 03)