JavaScript botnet code leaked to Internet
By
Robert McMillan
,
IDG News Service
, 04/02/2007
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Software that could be used to turn a Web browser into an unwitting hacker's tool has been posted to the Internet, after it
was downloaded by a quick-thinking attendee at last month's Shmoocon hacker conference.
The software, called Jitko was written by Billy Hoffman, lead researcher at Spy Dynamics Inc. Hoffman demonstrated the code
on March 24 as part of a presentation on the dangers of JavaScript malware.
Hoffman had discovered a way to write a Web vulnerability scanner in JavaScript, a Web language that can run in any browser.
This technique circumvents JavaScript's security restrictions and, concerned that his Jitko code could be misused, Hoffman
says he took extra steps to prevent the code from getting out.
However, in order for his demonstration to work, he had to post the Jitko code somewhere on the Internet. "Very briefly you
could see the original URL of where the Jitko code got fetched," Hoffman said.
That was enough for show attendee Mike Schroll to snag a copy.
"I was sitting pretty close to the front and had my laptop out already," said Schroll, an information security consultant
with Security Management Partners, Inc. "The second I saw it i just started typing away."
Schroll posted the code to his Web site March 25, and submitted a link to the code on Digg.com. He removed the software several hours later at Hoffman's request.
Schroll said he posted the code because he thought it would be useful to other security professionals looking for ways to
illustrate just how dangerous a scripting attack can be. "I was pretty interested in it because we do some engagements with
clients where we do fake phishing sites," he said. "I wasn't trying to be nefarious or malicious."
The software was downloaded from his Web site about 100 times, Schroll said.
Over the past weekend, the code surfaced again, this time on the Sla.ckers.org online discussion forum.
With Jitko now public, security researchers worry it could be misused by criminals to scan internal networks for sensitive
information, or to build a malicious botnet code. "This particular tool is designed to take control of the Web browser," said
Jeremiah Grossman, chief technology officer with WhiteHat Security Inc. "It will crawl other Web sites and scan them, looking
for vulnerabilities."
Hoffman was sanguine about the release of his tool, saying that criminals would probably have been able to develop something
similar to his short, 800-line application.
"It's kind of a tragedy that this ended up getting released," Hoffman said. "But in reality the bad guys probably knew this
and even if they didn't have it they were probably a couple of months away."
He said he's not angry at Schroll for snagging and releasing the Jitko code. "He probably did what any curious individual
would have done," he said. "I really can't fault someone for being curious because that's what my job is."
The IDG News Service is a Network World affiliate.
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