Windows DLL load hijacking exploits go wild

Researcher claims 41 Microsoft apps are vulnerable, need patching

Less than 24 hours after Microsoft said it couldn't patch Windows to fix a systemic problem, attack code appeared Tuesday to exploit the company's software.

Also on Tuesday, a security firm that's been researching the issue for the last nine months said 41 of Microsoft's own programs can be remotely exploited using DLL load hijacking, and named two of them.

On Monday, Microsoft confirmed reports of unpatched -- or zero-day -- vulnerabilities in a large number of Windows programs, then published a tool it said would block known attacks. At the same time, the company said it would not patch Windows because doing so would cripple existing applications.

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Less than 24 hours after Microsoft said it couldn't patch Windows to fix a systemic problem, attack code appeared Tuesday to exploit the company's software.

Also on Tuesday, a security firm that's been researching the issue for the last nine months said 41 of Microsoft's own programs can be remotely exploited using DLL load hijacking, and named two of them.

On Monday, Microsoft confirmed reports of unpatched -- or zero-day -- vulnerabilities in a large number of Windows programs, then published a tool it said would block known attacks. At the same time, the company said it would not patch Windows because doing so would cripple existing applications.

Microsoft also declined to say whether any of its own applications contain bugs that attackers could exploit, saying only that it is investigating.

Many Windows applications don't call code libraries -- dubbed "dynamic-link library," or "DLL" -- using the full pathname, but instead use only the filename, giving hackers wiggle room that they can then exploit by tricking the application into loading a malicious file with the same name as a required DLL.

If attackers can dupe users into visiting malicious Web sites or remote shares, or get them to plug in a USB drive -- and in some cases con them into opening a file -- they can hijack the PC and plant malware on the machine.

By Tuesday, at least four exploits of what some call "binary planting" attacks, others dub "DLL load hijacking" attacks, had been published to a well-known hacker site. Two of the exploits targeted Microsoft-made software, including PowerPoint 2010, the presentation maker in Office 2010, and Windows Live Mail, a free e-mail client bundled with Vista but available as a free download for Windows 7 customers.

Other exploits aimed at leveraging DLL load hijacking bugs in uTorrent and Wireshark, a BitTorrent client and network protocol analyzer, respectively.

At the same time, a Slovenian security company claimed that it reported bugs in two Microsoft-made programs last March.

"We're going to publish a list of the vulnerable apps we found sometime soon," said Mitja Kolsek, the CEO of Acros Security. "However, since HD Moore's toolkit is already being used for finding vulnerable apps and at this point hundreds of good and bad guys already know about it, I can say that the two we fully-disclosed to Microsoft were in Windows Address Book/Windows Contacts and Windows Program Manager Group Converter.

HD Moore is the American researcher who kicked off a small wave of DLL load hijacking reports last week when announced he had found 40 vulnerable Windows applications . On Monday, Moore published an auditing tool that others can use to detect vulnerable software. When combined with an exploit added that same day to Metasploit, the open-source hacking toolkit that Moore authored, the tool's results produce what he called a "point-and-shoot" attack .

All four of the exploits that went public Tuesday appear to be based on Moore's Metasploit attack code.