New code-execution bug found in Windows and 40 apps

When 'safe' files aren't

Microsoft Windows and about 40 applications that run on it are vulnerable to remote-code execution attacks that are "trivial" to carry out, a noted security researcher warned Wednesday.

The flaw involves the way Windows loads "safe" file types from remote network locations, and is almost identical to one that Apple excised in iTunes last week, H D Moore, CSO and chief architect of the Metasploit project, told The Register. He said the bug is “trivial” to remotely exploit, but wasn't authorized to provide additional details about techniques or other vulnerable applications.

According to a more detailed advisory for the iTunes fix, the “binary planting” vulnerability allowed attackers to execute malicious code on Windows machines by getting the media player to open a file located on the same network share as a maliciously designed DLL file.

“All a remote attacker has to do is plant a malicious DLL with a specific name on a network share and get the user to open a media file from this network location in iTunes – which should require minimal social engineering,” the advisory, which was written by ACROS Security, stated.

“Since Windows systems by default have the Web Client service running – which makes remote network shares accessible via WebDAV – the malicious DLL can also be deployed from an Internet-based network share as long as the intermediate firewalls allow outbound HTTP traffic to the Internet.”

Microsoft said in a statement it is investigating the report.

Moore said users can protect themselves against attacks by blocking outbound SMB connections on ports 445 and 139 and on WebDAV. That will stop attacks that originate over the internet, but users may still be susceptible to LAN-based attacks where an attacker has planted malicious DLLs on a network share. In that respect, it's similar to workaround advice given for the Windows shortcut flaw that Microsoft patched earlier this month. ®

This article was updated to include comment from Microsoft.

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