The Register® — Biting the hand that feeds IT

Feeds

Attackers improve on JavaScript trickery

Obfuscation is my middle name

Regcast training : Hyper-V 3.0, VM high availability and disaster recovery

CanSecWest As JavaScript becomes an increasingly key component of online attacks, attackers are investing more energy in obfuscation and other techniques to make defenders' attempts at reverse engineering more difficult, a security researcher told attendees at the annual CanSecWest conference on Wednesday.

Attackers have adopted the same techniques used to hide the purpose of other types of malicious code, such as splitting up the code into many components and the use of custom encoders, to obfuscate JavaScript, said Jose Nazario, senior security engineer at network-protection firm Arbor Networks. Other advances include the addition of functions aimed at detecting any attempts at debugging or running the program in a virtual machine, he said.

"There is a lot of defensive JavaScript coming around," Nazario told attendees. "Attackers now will kill alerts and kill all sorts of inspection routines. They also will frequently only let a single IP (Internet protocol) address download the JavaScript."

A year ago, researchers warned about future worms that could spread through users' online profiles and data using JavaScript and interactive Web technology, similar to the Samy worm that infected MySpace in 2005. The increasing use of asynchronous JavaScript and XML (AJAX) for sharing data and adding interactivity to wesites has compounded the danger.

In the last year, malicious software written in JavaScript and AJAX has moved from an interesting research topic to a significant threat on the Internet, increasingly used by attackers to compromise users' computers. In February, researchers at security firm Websense discovered that the website for the Dolphin Stadium had been compromised in an attack that did not deface the site, but rather had infected the home page with malicious JavaScript code that attempted to force visitors to download a Trojan horse from one of three sites in China. Further research by incident responders found at least three dozen other sites that hosted similar code.

Nearly identical attacks, likely perpetrated by the same group, used the recent Microsoft animated-cursor flaw to compromise computers as well.

"I would not say that this is the end of their attacks," said Dan Hubbard, vice president of security research for Websense, said in February.

The advances in sophistication of malicious JavaScript make it more important for researchers to use proper debuggers and keep copies of any obfuscated code, Arbor's Nazario said. Many of the latest techniques are not aimed at fooling the victim, but the malware analyst, he added.

"The object is to make the attack vector that much more opaque, not just to your system, but to the analyst as well," Nazario said.

Other security experts have agreed that malicious software written in JavaScript will become more powerful.

Last month, security researcher Billy Hoffman showed off a JavaScript vulnerability scanner that could turn the computer of any visitor to a malicious Web site into an unwitting accomplice in an attack. While the proof-of-concept program, known as Jikto, had only rudimentary functionality, further development could create software that essentially turns Web site visitors into temporary zombies, said Hoffman, lead researcher for Web security firm SPI Dynamics.

"This is only going to make things worse," Hoffman said at the time. "It is like you (the victim) are in a bot net but without all the traditional malware traces that bot software usually leaves behind."

In the week following the presentation, someone leaked the source code - which Hoffman had intended to keep private - to the internet. This article originally appeared in Security Focus.

Copyright © 2007, SecurityFocus

Agentless Backup is Not a Myth

Latest Comments

NoScript

Try the NoScript extension for Firefox. The default settings disable javascript, but you can enable on a per-site basis, or just temporarily allow if you don't want to add to the whitelist yet.

http://noscript.net/

0
0

example of attack

I run mozilla on linux, so do not expect much in the way of web attacks, as such is usually oriented toward Window machines.

A couple days ago I was doing online reasearch on some obscure electronics devices, opening a few tabs associated with a Google search. In addition, this produced an unwanted small window, without the full features of a new mozilla window. I rarely get pop-under windows. This was more like a pop-up, which I have blocked in mozilla. I usually close out these rare pop-unders manually.

The contents of this window was something to the effect that my computer still contained information about porn sites that I had visited, offering to clean this from my computer. There appeared to be a couple of buttons at the bottom to accept or decline this offer. Since Google has not sent me to any a porn sites (like it formerly did) in over a year, I was sure this was a ruse. Ignoring the accept/ decline buttons , I tried the upper right-handed X to close it out.

It turned out, the window was just a single image (I am guessing), no active buttons at all. In any event the "clean my porn" operation commensed in a newly opened small real broswer window. I think it had as many tabs as my original mozilla window. My original tabbed mozilla window resized smaller. I did manage to close the new "porn cleaning" window. It complained that it had not finished its task. Mozilla completely died, which was preferable to the "porn cleaner" completing whatever it was up to. I have no idea what it was trying to do to my computer.

If I see any these in the future I may try a "killall java"

or possibly a "killall mozilla-bin" Attempting to close the inital image or popup window, or whatever it was did not get rid of it.

In 7 years of Linux usage, this is the only browser attack that I have ever witnessed, at least that I know about.

0
0

Prompt users to disable javascript

... and then laugh at all the web developers that can't do a simple Submit button without feeling some kind of bizarre need to implement JS.

I always suspected that JS should be used for nothing but "fluff" and being on the front-line so to speak has confirmed that suspicion. I run the website for a fairly small company (in house), small enough that I actually have to speak to the punters periodically... which, while occasionally irritating, is actually extremely informative. We have an e-commerce site that keeps working with JS and cookies disabled; some of the features pack up of course but it doesn't actually break the site as a whole.

0
0

More from The Register

 breaking news
NSA PRISM snoop-gate: Won't someone think of the children, wails Apple
10,000 things probed, mostly about missing kids, Alzheimer patients, we're told
 breaking news
NSA PRISM-gate: Relax, GCHQ spooks 'keep us safe', says Cameron
Whatever they are up to, it's all above board, we're told
PRISM snitch claims NSA hacked Chinese targets since 2009
Snowden suddenly looks safer in Hong Kong after revelations
 breaking news
US chief spook: Look, we only want to spy on 6.66 BEELLLION of you
Americans assured they are not in the NSA's sights
Speech-to-text drives motorists to distraction
Will talking to you mean I crash into that car up ahead, Siri?
 breaking news
Number of cops abusing Police National Computer access on the rise
Only a telegram from the Queen can get you off it
DHS warns of vulns in hospital medical equipment
Has your doctor's anasthesia machine been hacked?
 breaking news
'BadNews is malware' says outfit that found it
Google says code harmless but Lookout says code base is evolving
Panda-peddlers cuffed for chess gambling gambit
More porridge on the menu for Chinese coders after second offence
 breaking news
Yes, maybe we should keep hackers in the clink for YEARS, mulls EU
Watch out black hats, they just might throw away the key