NIST Site Search
Search NIST.GOV
Custom Search
[Official NIST.GOV TIME]
Product Research

Advertise on this site
Firefox JavaScript Reentrant Vulnerability
Two Hackers at the ToorCon hacker conference demonstrated a flaw in Firefox that could lead to arbitrary code execution. The problem is with how Firefox implements JavaScript. Easy mitigation step, see below. (Updates: Proof of Concept code posted... The two hackers may have overstated the problem.) No Longer Supported
If you just want the skinny on the Firefox vulnerability click here. We're starting off with a little background on Javascript. See important Updates below.

We've said it many times before, the Internet is not a safe place, diligence is key. Though we feel that Firefox is more secure than Internet Explorer this is large part due to the lack of ActiveX support. But there are many other avenues to attack the web browser other than ActiveX. One of those is Javascript. Javascript is a interpreted programming language that works on the client side of the connection (as opposed to the server side). When your web browser loads a web page and sees Javascript on the page it interprets the code and does what its told to do. This sounds inherently dangerous since you have no control over what may be hidden in the HTML of some web page. But Javascript was written from the ground up to run within the confines of the web browser and as such its powers are limited. Most often used for simple tasks such as mouse rollovers (eg; changing a graphic when you highlight a button, or changing a text color when you float the cursor over the text) or validating form input. It is also often used in flyout style menus. It is usually harmless.

But the bad guys have figured out ways to use it maliciously. One such use is in Cross-Site Scripting (XSS) where Javascript is fed through some site's form entry (etc) that will echo it back to the user. When this is done it appears that whatever the Javascript did in the browser actually came from the website. So when you think you are entering your pin number on the banks site you may actually be entering it on the phishing / hackers site (there are other malicious uses for XSS as well). XSS vulnerable sites are everywhere. This author went hunting for them and found 2 major media sites that are vulnerable in less than 20 minutes.

Because Javascript must be interpreted by the browser to do things any oversight on the part of the browser programmers could be disastrous. A simple example would be Javascript used to load an image, if that routine could instead be used to load a local file with parameters a hacker could use this to run commands to download and start any malicious content they wanted. This would, in affect, make Javascript as dangerous as ActiveX (ActiveX can do almost anything if you let it. Its very powerful, it can also be very dangerous if used or configured incorrectly). These type problems with Javascript are rare but have come up from time to time.

Latest Firefox JavaScript Reentrant Vulnerability: (see updates below)

Two self-professed hackers, Mischa Spiegelmock and Andrew Wbeelsoi, gave a slide show at the ToorCon hacker conference showing Firefox being exploited to run arbitrary code. According to Spiegelmock the Firefox Javascript implementation is a "complete mess," and "is impossible to patch." Of course this this comes from a couple of hackers who's presentation was described on ToorCon as "New ways of getting your load onto your quivering victim's stack Reaching into the hearts and minds (also the genitals) of users" and comments in the slide presentation like "Hahahahahahaha stick that in your pipes and smoke it Firefox fanboys!". According to people who saw the presentation it appeared to show enough to figure out how to recreate the exploit. So far the vulnerability has not been confirmed and it is possible this is all a ruse or greatly exaggerated. But the folks at Mozilla seem to have seen enough to be taking this serious.

Of course this could also be the real deal. If that is the case Firefox has a very potent vulnerability just waiting to be exploited. Javascript can often be loaded in to bulletin board posts and blogs so random surfing would not be safe. Of course it can also be used in targeted attacks via eMail links, or loaded on to compromised web servers. It will be imperative that this get fixed quickly. If you are using a pre-1.5 version of Firefox and don't want to upgrade you should install the NoScript Extension (see below) immediately. Firefox 1.5x will be updated to fix this problem, previous versions will not.

The vulnerability as presented could lead to running arbitrary executable code within the security context of the user. In other words make Firefox install whatever the bad guys want installed assuming your login has the rights to install software.

Mitigation:
  • If you run Firefox you should immediately install the NoScript Extension. This script will prompt you when a page tries to run Javascript and give you the option to let it run. You can tell it to run just for this browser session or you can whitelist the site so that it always runs Javascript from that site. Some sites are very dependent on Javascript and won't show you anything without it. Some sites display nicely without it. We recommend whitelisting sites you visit often. Unless you do you'll never know what content you're missing out on. Some of the content might load using standard HTML, other content might load using JavaScript. For instance this site uses Javascript in several of the sidebar boxes.
  • You could use Internet Explorer since it is not vulnerable to this particular bug. But it currently has several unpatched vulnerabilities of its own. Since it still commands about 75-80% of the browser market hackers often target its vulnerabilities harder than those in Firefox (besides their is a "stick it to the man" mentality in attacking MS).


References:


Updates:
  • If you can't trust a couple of hackers who can you trust!! Quotes from Mozilla's interview with one of the two hackers that gave the presentation: "The main purpose of our talk was to be humorous." "I personally have not gotten it to result in code execution, nor do I know of anyone who has." The PoC can lead to a browser crash. They also admitted to not having "30 undisclosed Firefox vulnerabilities".
  • Proof of Concept code has been posted on the web. Now its only a matter of time before this vulnerability is exploited in the wild.


Vulnerable - Windows, Mac, Linux. Apparently all versions of Firefox.

Share or Bookmark this Article Using:
No Longer Supported



Google
WebNIST.org
NIST.govSecurityFocus.com





Posted by NIST.org on Monday 02 October 2006 - 04:13:29 | |printer friendly
Translate to: French German Italian Spanish Portuguese GTM_LAN_DUTCH Russian Chinese Arabic Korean English
Google Ads




Headlines

»Filling the Gap: NIST Document to Protect Federal Information in Nonfederal Information Systems
»Cyber Security: Your Mother Was Right, Sharing is Good, And NIST Has Some Help on How
»2014 Cybersecurity Education Meeting Emphasizes Presidential Ready to Work Initiative
»UMD and NIST Announce the Creation of the Joint Center for Quantum Information and Computer Science
»NISTaposs Cloud Computing Roadmap Details Research Requirements and Action Plans
»NIST Awards Contract to MITRE to Support Cybersecurity Center of Excellence
»NCCoE Fall Open House
»NCCoE Seeks Comments on Mobile Device Security Building Block
»Three Pilot Projects Receive Grants to Improve Online Security and Privacy
»NIST Megacities Carbon Project Named aposProject to Watchapos by United Nations
»NIST Announces FY 2014 Small Business Innovation Research Awards
»NIST Helps Develop New Standard for Microsensor Technology
»New Forensic Subcommittee on Digital Evidence Added to Organization of Scientific Area Committees
»NIST Team Honored for Work on Military Smartphone Apps, Security
»NIST Vetting Guide Helps in Testing Mobile Apps to Learn What They Really Do


Date published: not known
Details

»WordPress Releases Security Update
Original release date: November 21, 2014 WordPress 4.0.1 has been released to address multipl ...
»Drupal Releases Security Advisory
Original release date: November 20, 2014 Drupal has released an advisory to address multiple ...
»Google Releases Security Update for Chrome
Original release date: November 19, 2014 Google has released Chrome 39.0.2171.65 for Windows, ...
»Microsoft Releases Out-of-Band Security Bulletin for Windows Kerberos Vulnerability
Original release date: November 18, 2014 | Last revised: November 19, 2014 Microsoft has rele ...
»IC3 Releases Scam Alert for Fraudulent Online Advertisements
Original release date: November 18, 2014 The Internet Crime Complaint Center (IC3) released a ...
»Apple Releases Security Updates for iOS, OS X Yosemite, and Apple TV
Original release date: November 17, 2014 Apple released security updates for iOS devices, OS ...
»IC3 Releases “Tech Support” Themed Scam Alert
Original release date: November 13, 2014 The Internet Crime Complaint Center (IC3), a partner ...
»Google Releases Security Update for Chrome
Original release date: November 11, 2014 Google has released Chrome 38.0.2125.122 for Windows ...
»Adobe Releases Security Updates for Flash Player
Original release date: November 11, 2014 Adobe has released security updates to address multi ...
»Microsoft Releases November 2014 Security Bulletin
Original release date: November 11, 2014 Microsoft has released updates to address vulnerabil ...


Date published: not known
Details

»Botconf 2014 preview
Many VB authors and presenters to speak at second botnet-fighting conference. Last year, I attended ...
»VB2014 paper: Sweeping the IP space: the hunt for evil on the Internet
Dhia Mahjoub explains how the topology of the AS graph can be used to uncover hotspots of maliciousn ...
»Report: VB100 comparative review on Windows 8.1
40 out of 48 tested products earn VB100 award. If you follow the security news, you may believe that ...
»Out-of-band patch released for all Windows versions
Kerberos bug means one set of credentials suffices to rule them all. If you are a Windows systems ad ...
»VB2014 paper: Optimized mal-ops. Hack the ad network like a boss
Why buying ad space makes perfect sense for those wanting to spread malware. Over the next few month ...
»Book review: Bulletproof SSL and TLS
Must-read for anyone working with one of the Internet's most important protocols. I was reading Ivan ...
»VB2014 paper: Bootkits: past, present & future
Despite better defences, the era of bootkits is certainly not behind us. Over the next few months, w ...
»Stuxnet infected Natanz plant via carefully selected targets rather than escape from it
Five initial victims of infamous worm named. Today, as Wired journalist Kim Zetter publishes her boo ...
»VB2014 paper: Apple without a shell - iOS under targeted attack
Developer Enterprise Program recently found to be used by WireLurker. Over the next few months, we w ...


Date published: not known
Details

»Privacy Groups Release 'Detekt' Tool to Spot Spyware
Privacy advocates have joined together to release a tool for identifying cyber espionage malware.
»Cloud Security By The Numbers
Quantifying the perceptions around cloud security practices.
»The Week When Attackers Started Winning The War On Trust
The misuse of keys and certificates is not exotic or hypothetical. It's a real threat that could und ...
»When Every Minute Counts (Part 2)
Acting on key Indicators of Attack for incident response is crucial.
»Russian Cyber Espionage Under The Microscope
New report shows level of coordination and strategy by three main groups of cyberspies out of Russia ...
»New Citadel Attack Targets Password Managers
IBM researchers have found signs that the prolific data steal Trojan is now being used to attack wid ...
»You're Doing BYOD Wrong: These Numbers Prove It
Almost 40% of users who connect personal mobile devices to corporate networks have no lock-screen me ...
»Surveillance Cameras Next On The Insecure IoT List
Three buffer overflow vulnerabilities leave HikVision video recorders open to remote code execution.
»Enter The Digital Risk Officer
In the brave new world of digital risk management, a CISO would report up to a DRO who manages risk ...


Date published: Sun, 23 Nov 2014 02:55:12 EST
Details
Main Menu
· Home
Current Security News
 
SANS Internet Storm Center, InfoCON: green

» Infocon: green

» ISC StormCast for Friday, November 21st 2014 http://isc.sans.edu/podcastdetail.html?id=4247, (Fri, Nov 21st)
[20 Nov 2014 08:30pm]

» Google Web "Firing Range" Available, (Thu, Nov 20th)
[20 Nov 2014 01:03pm]

» Critical WordPress XSS Update, (Thu, Nov 20th)
[20 Nov 2014 12:42pm]

» ISC StormCast for Thursday, November 20th 2014 http://isc.sans.edu/podcastdetail.html?id=4245, (Thu, Nov 20th)
[19 Nov 2014 05:51pm]

» "Big Data" Needs a Trip to the Security Chiropracter!, (Wed, Nov 19th)
[19 Nov 2014 12:18pm]

» ISC StormCast for Wednesday, November 19th 2014 http://isc.sans.edu/podcastdetail.html?id=4243, (Wed, Nov 19th)
[18 Nov 2014 08:28pm]

» Microsoft November out-of-cycle patch MS14-068, (Tue, Nov 18th)
[18 Nov 2014 05:15pm]

» Microsoft Will Release MS14-068 Later Today, (Tue, Nov 18th)
[18 Nov 2014 09:24am]

» ISC StormCast for Tuesday, November 18th 2014 http://isc.sans.edu/podcastdetail.html?id=4241, (Tue, Nov 18th)
[17 Nov 2014 07:19pm]

» Updates for OS X , iOS and Apple TV, (Mon, Nov 17th)
[17 Nov 2014 01:22pm]

***
CNET News.com

» Microsoft defends opening Hotmail account of blogger in espionage case
[20 Mar 2014 06:47pm]

» Syria's Internet goes dark for several hours
[20 Mar 2014 04:25pm]

» Symantec fires CEO Steve Bennett
[20 Mar 2014 03:07pm]

» Microsoft sniffed blogger's Hotmail account to trace leak
[20 Mar 2014 01:28pm]

» Microsoft sniffed private Hotmail account to trace trade secret leak
[20 Mar 2014 01:28pm]

» IBM's new services zero in on fraud, financial crime
[20 Mar 2014 07:31am]

» Despite assault on privacy, Page sees value in online openness
[19 Mar 2014 08:00pm]

» Hackers transform EA Web page into Apple ID phishing scheme
[19 Mar 2014 05:21pm]

» NSA top lawyer says tech giants knew about data collection
[19 Mar 2014 02:57pm]

» Microsoft touts study showing the cost of pirated software
[19 Mar 2014 06:55am]

» Microsoft touts study showing cost of malware in pirated software
[19 Mar 2014 06:55am]

» How to spy on your lover, the smartphone way
[18 Mar 2014 01:24pm]

» Mt. Gox update lets users see their Bitcoin balances
[18 Mar 2014 06:38am]

» Fake Malaysia Airlines links spread malware
[17 Mar 2014 05:12pm]

» IBM: No, we did not help NSA spy on customers
[17 Mar 2014 01:15pm]

***

***



***


More IT Security
News Feeds
More Sponsors

Advertise on this site
RSS Feeds
Our news can be syndicated by using these rss feeds.
rss1.0
rss2.0
rdf
Symantec News

NIST.org is in no way connected to the U.S. government site NIST.gov

This site is © John Herron, CISSP. All Rights Reserved.

Please visit daily to stay up to date on all your IT Security compliance issues.

http://www.nist.org -
Hosted by BlueHost. We've never had a better hosting company.
{THEMEDISCLAIMER}