Microsoft still mum on programs prone to DLL hijacking attacks

Instead, it offers automated tool to simplify attack blocking setup

Microsoft on Tuesday again abstained from naming which of its Windows programs, if any, contain bugs that could lead to widespread "DLL load hijacking" attacks.

Also on Tuesday, the company published an automated tool to make it easier for users to block attacks exploiting vulnerabilities in a host of Windows applications.

The DLL load hijacking vulnerabilities exist in many Windows applications because the programs don't call code libraries -- dubbed "dynamic-link library," or "DLL" -- using the full pathname, but instead use only the filename. Criminals can exploit that by tricking the application into loading a malicious file with the same name as the required DLL. The result: Hackers can hijack the PC and plant malware on the machine.

"Microsoft plans to address those of our products affected by this issue in the most appropriate way for customers," said Jerry Bryant, a group manager with the Microsoft Security Response Center, in a Tuesday entry on that team's blog . "This will primarily be in the form of security updates or defense-in-depth updates."

Although Microsoft again declined to call out its vulnerable software, outside researchers have identified as potential targets a number of its high-profile apps, including Word 2007, PowerPoint 2007 and 2010, Address Book and Windows Contact, and Windows Live Mail.

Other vendors' software may also be at risk, including Mozilla's Firefox, Google's Chrome, and Adobe's Photoshop.

Bryant hinted that some Microsoft software could be exploited. "Due to the fact that customers need to click through a series of warnings and dialogs to open a malicious file, we rate most of these vulnerabilities as Important," he said, referring to the second-highest threat ranking in the company's four-step scoring system.

Microsoft typically uses Important to describe bugs that can be exploited remotely -- via the Internet or e-mail, for example -- but which also require that the user assist the attack in some way, usually by clicking through warnings or opening a malicious file.

In another blog , Jonathan Ness, an engineer with MSRC, and Maarten Van Horenbeeck, an MSRC program manager, described how customers can deploy and use a tool the company first offered Aug. 23 .

That tool blocks the loading of DLLs from remote directories, such as those on USB drives, Web sites and an organization's network, and is aimed at enterprise IT personnel.

Not surprisingly, Microsoft acknowledged that users have asked for more help with the tool. Shortly after its release, IT professionals complained that the tool was confusing and asked colleagues for advice on how to configure it.

To simplify things, Microsoft has posted a "Fix It" tool on its support site that automatically blocks any DLLs from loading from WebDAV or SMB (Server Message Block) shares, two of the most likely attack vectors. Users must still download and install the original tool, however.

Ness and Van Horenbeeck also downplayed the threat to some extent, saying that DLL load hijacking bugs cannot be exploited via "drive-by" attacks, where a user's PC is infected as soon as he or she browses to a malicious site.

"A victim would need to browse to a malicious WebDAV server or a malicious SMB server and double-click a file in the Windows Explorer window that the malicious server displays," they said.

Microsoft has known of the issue since at least August 2009 , when researchers with the University of California Davis notified the company of their work. There's evidence, however, of reports as far back as 2000, and attacks exploiting the flaw the following year, when the Nimda worm leveraged the bug in Office 2000.

HD Moore, chief security officer at Rapid7 and the creator of the Metasploit penetration testing toolkit, was the first to reveal the potential attacks when, on Aug. 19, he said he'd found 40 vulnerable Windows applications . Moore was followed by other researchers who claimed different numbers of at-risk programs, ranging from more than 200 to fewer than 30.

Some vendors have already patched the problem in their software. Both uTorrent and Wireshark, a BitTorrent client and network protocol analyzer, respectively, have been updated to address the bug.

Others are working on a fix. "We're testing our own Firefox-specific fixes and plan to get them out to users soon," Mozilla's security team said in an e-mail reply to questions last week.

Even so, Microsoft said patches may be long in coming to some users. "We recognize that it may take quite a bit of time for all affected applications to be updated and for some, an update may not be possible," Bryant admitted.

In lieu of patches, the blocking tool is the best defense, he continued. With that in mind, Microsoft plans to make the tool available "within the next couple of weeks" for downloading and deployment using Windows Server Update Services (WSUS), Microsoft's most-used business patch management mechanism.

The company is also thinking about pushing the tool to everyone, including consumers, via Windows Update, although it would be switched off by default, said Bryant.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@ix.netcom.com .

Read more about security in Computerworld's Security Topic Center.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags securityMicrosoftoperating systemssoftwareWindows

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld (US)
Show Comments

Cool Tech

Breitling Superocean Heritage Chronographe 44

Learn more >

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?