Enterprise Software

New threats show browser vulnerabilities don't play favorites

Browser vulnerabilities are making the rounds this week, as different threats have surfaced for Mozilla, Firefox, Netscape, and Internet Explorer. In this edition of the IT Locksmith, learn more about these various threats, find out how you can best protect your organization from these vulnerabilities, and see what else has recently surfaced in the security world.

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New vulnerabilities are haunting Mozilla, Firefox, and Netscape browsers, while different threats have surfaced in Outlook and Internet Explorer. Meanwhile, IM and P2P threats surge.


Secunia has reported, and Mozilla has confirmed, an information disclosure vulnerability in the Firefox browser—including the latest update (version 1.0.2), which is only a few weeks old (released March 21). In fact, troubles for the increasingly popular browser are coming so fast and furious that mozillaZine has reported that a new Firefox release candidate has already replaced the Firefox release candidate 1.0.3, which became available on April 5.

Mozilla released the new release candidate (also designated 1.0.3) the very next day. Be forewarned that this release candidate 1.0.3, and probably the eventual release version as well, will likely cause problems with a number of extensions.

Below are links to Secunia's reports about each threat:

The information disclosure vulnerability exposes random memory areas to malicious Web sites, and users would never be aware of it. As you would expect, it's mostly ASCII garbage, but there are definitely real information disclosures too, so this is a very real threat.

Secunia offers a Mozilla Products Arbitrary Memory Exposure Test to help you determine if your system is vulnerable to the new vulnerability. Using IE6, I went to the site and found no problem, but Firefox was definitely exposing arbitrary chunks of my memory. So if you're using Firefox, Mozilla, or even Netscape, I highly recommend running a quick test from Secunia's Web site.

Another recent report, this one coming from SecuriTeam.com (and credited to mikx), appears very similar, and it almost certainly refers to the same vulnerability discussed in the Secunia reports. (Secunia doesn't list MITRE CAN designations, so I can't be certain.) Below are links to the Common Vulnerabilities and Exposures (CVE) reports.

Unfortunately, SecuriTeam.com has published links to proof-of-concept code. Dubbed Firescrolling, Fireflashing, Firetabbing, and Firedragging, all of these threats involve Java-based attacks.

But don't think Mozilla's security woes means Microsoft's getting off easy this week. eEye Digital Security is reporting that its engineers have discovered a new vulnerability in Outlook and Internet Explorer. eEye has sent the information to Microsoft, and this security vendor doesn't provide any details about vulnerabilities until the vendor releases a patch.

So far, all we know from the disclosure is that the vulnerability entails a remote code execution threat to multiple versions of Internet Explorer. News.com offers a little more information in its report, implying that would-be attackers could exploit the IE vulnerability by getting users to surf across a banner ad.

In addition, eEye published an earlier vulnerability that also affects IE as well as Outlook. The security vendor notified Microsoft of the vulnerability on March 16, but the software giant has not yet released a patch. Because eEye publishes no details about new threats that could help script kiddies, it's difficult to determine which of the two IE threats is generating online reports elsewhere.


Most—and possibly all—Mozilla-family browsers are vulnerable to the Java-based information disclosure threat. Specifically, all Mozilla browsers from 0.x through 1.7.x are vulnerable, as well as all Firefox versions, including 1.0.2 (the most recent release). Netscape 6.x and 7.x are definitely vulnerable, but Secunia reports that other versions may also be susceptible.

While unspecified, multiple versions of IE on various platforms are vulnerable to one or both of the remote code execution threats discovered by eEye.

Risk level - Critical

All three of these threats range from serious to critical. At this time, vendors have yet to release any patches. However, I haven't seen any reports that attackers are attempting to actively exploit any of the three threats either.

Mitigating factors

Since all three threats appear to apply to default installations of the browsers, the only mitigating factor is that no one is exploiting the vulnerabilities yet. Thanks to the availability of more details about the Mozilla-family vulnerability, we know attackers can only exploit this threat if users browse to a malicious Web site. However, thanks to the publishing of proof-of-concept code for the Mozilla-family browsers, we can expect to see exploits soon.

Of course, while you can switch to Firefox to avoid the latest IE vulnerability, you'll then have to deal with the new Firefox vulnerability instead—and it appears to be nearly as dangerous.


All of the Mozilla, Firefox, and Navigator threats appear to involve Java. So, until Mozilla releases a patch, disabling JavaScript will block any attack attempts in the meantime. The April 6 version of Firefox release candidate 1.0.3 (as opposed to the April 5 version) does address this JavaScript vulnerability. However, it will reportedly wreak havoc with some extensions, so it's strictly a beta test version for now.

No workaround is available at this time for the IE and Outlook threats.

Final word

Well, not to belabor the obvious, but as I've always said, a big reason that hackers hit Microsoft so often is because it's the biggest target. Knowing this is one reason many people have turned to Firefox.

I like Firefox; I use Firefox every day. But I've never been under the illusion that it's completely secure or that it wouldn't suddenly begin to develop a lot of leaks when it became popular enough for people to take some serious shots at it.

As Firefox and Mozilla become more popular, I expect to see more vulnerabilities and patches—it's just common sense. For the time being, Firefox only has about 9 percent of the market, so we can still expect to see plenty of problems emerging in Internet Explorer as well.

Until this week, I had simply switched browsers when a new vulnerability appeared in one or the other. But now both browsers I regularly use have serious vulnerabilities, so I'm stuck until a usable patch is available.

Also watch for …

  • News.com has summarized a number of reports about instant messaging and P2P networks, and none of them are good. The short version is that IM and P2P attacks have surged 250 percent as better antispam filters have reduced spam on e-mail servers. Ranging from viruses and worms to phishing ventures, the attacks mostly affect Yahoo!, MSN Messenger, AOL, and Windows Messenger.
    Again, that's most likely because these vendors have the most target-rich audiences. If other IM clients become more popular, attackers will begin targeting them. Only 11 percent of the attacks actually used a known vulnerability; presumably, the rest just relied on users opening anything anyone sent to them.
  • If you needed any proof that phishing is becoming a big danger, you need only note that Microsoft recently filed 117 lawsuits over the creation of fake Microsoft sites. Unlike viruses, which are a profit center for some software companies, it appears that the phishing threat is becoming so dangerous that the big boys are going to fight this battle for us.
  • News.com has also reported how phishing is rapidly migrating from e-mail to instant messaging services. For some interesting numbers, check out Antiphishing.org or the organization's February 2005 PDF report.
  • Users can patch Firefox 1.0 (and most likely later versions) to block more popup ads. But this poses a new problem: As Firefox and other popup-blocking browsers gain market share, advertisers are turning to a new kind of popup that uses plug-ins. Because many sites use legitimate popup windows for various features, browsers typically don't block them.
  • Because of the antiprivacy, procorporate culture in Japan, it may be hard to believe that the country just passed a draconian privacy theft law, which will hold designated corporate privacy officers and staff criminally liable for security breaches resulting in the disclosure of personal records. The new law took effect April 1 but doesn't appear to be either a joke or wishful thinking. The law applies to companies holding more than 5,000 such records, and those found responsible for failing to follow the strict new rules can receive a fine and up to six months in jail. Wow—do we ever need that here! Everyone send a copy of this to your congressperson!

John McCormick is a security consultant and well-known author in the field of IT, with more than 17,000 published articles. He has written the IT Locksmith column for TechRepublic for more than four years.

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