New Security Hole in AOL Messenger

Associated Press

January 2, 2002

A security hole in AOL Time Warner¡äs Instant Messenger program used by millions of people worldwide can let a hacker take full control of a victim¡äs computer, according to security researchers and the company. An AOL spokesman said the problem will be fixed soon, and users won¡ät have to download anything.

"WE HAVE IDENTIFIED the issue and have developed a resolution that should be deployed in the next day or two," AOL¡äs Andrew Weinstein said. "To our knowledge, this issue has not affected any users."

The problem affects the newest versions as well as many earlier iterations of AOL¡äs Instant Messenger program. Only the Windows version is at risk ¡ª Instant Messenger for Macintosh, Palm and other platforms are not.

Discovered by a loose team of international researchers called ¡äw00w00,¡ä the hole is a "buffer overflow," like the problem recently found in Microsoft¡äs Windows XP. (MSNBC is a Microsoft - NBC joint venture.)

By sending a stream of junk messages to the program, a hacker can overwhelm the software and make the victim¡äs computer run any commands the hacker wants.

"You could do just about anything, (you could) delete files on the computer or take over the machine," w00w00 founder Matt Conover said.

Conover said w00w00 has over 30 active members from 14 states and nine countries. Until AOL¡äs fix is released, Conover said, Instant Messenger users should restrict incoming messages to friends on their "Buddy List."

"It will at least keep someone from attacking you at random," Conover said, but it wouldn¡ät help if the attack code is added to a virus that propagates without the victim¡äs knowledge. AOL said it has not given its users any advice in the interim.

Conover said the group found the problem several weeks ago, but didn¡ät contact AOL until after Christmas. The group didn¡ät get any response from AOL through an e-mail during the holiday week, he said, so w00w00 released details ¡ª and a program that takes advantage of it ¡ª to public security mailing lists less than a week later.

The program released by w00w00 remotely shuts down a person¡äs Instant Messenger program, but could be modified to do more sinister things.

That practice is under scrutiny by security professionals. While some independent researchers argue for a "full disclosure" policy and say software vendors are trying to cover up their mistakes, many companies say users are better protected if the company has time to react.

Russ Cooper, who moderates a popular security mailing list and works for security firm TruSecure, said Conover¡¯s actions are irresponsible.

"I think it¡¯s better to provide details of the exploit and then let other people write the actual code," Cooper said. "Unfortunately, these are fundamentally naive people with a very childish view of the world."

Cooper said he let Conover send the information out through his mailing list, but only did so after noticing it was released through other channels as well.

Conover said w00w00 set a New Year¡äs deadline for sentimental reasons, because it was the anniversary of the group¡äs last major security release. He defended the disclosure of the attack program.

"This is the approach that w00w00 has historically taken to the problem," he said. "For us it means providing all the information we have available to the security community."

AOL¡äs Weinstein said the company would have appreciated more warning.

"We¡äd encourage any software programmer that discovers a vulnerability to bring it to our attention prior to releasing it," Weinstein said.

http://www.w00w00.org/advisories/aim.html