On August 23rd Microsoft released Microsoft Security Advisory (2269637): Insecure Library Loading Could Allow Remote Code Execution. It seems that if a program doesn't properly specify the path for a Dynamic-Link Library (DLL) an attacker can create a bogus DLL that will be loaded instead when a program tries to load the DLL. That DLL can contain code to install software, delete files, or do anything the user can do - or the program calling the DLL can do, if it has greater priveleges than the user.
What makes this bad mojo? This attack works over the network, so it can be performed by making a file available online that will cause a program on your computer to launch and call the bogus DLL. The attacker doesn't actually have to put anything on your machine, he only has to get you to open a remote file and if you are logged into your computer as an administrator (most home users and many small business users are) your computer is no longer yours.
This exploit works over networking protocols. The advisory specifically names WebDAV and SMB, but it will probably work over NFS (Suns Network File System) and AFP (Apple File Protocol) and maybe FTP as well.
Microsoft is providing workarounds to negate the problem, but is relying on the software companies to supply patches to their software to solve this problem. If Microsoft were to patch this issue on the operating system lot of programs would break, so at the time I write this they are not going to issue a patch. Here are the workarounds Microsoft is offering:
Mitigating Factors and Suggested Actions
Additional Suggested Actions
• Install updates from third-party vendors that address insecure library loading
Third-party vendors may release updates that address insecure library loading in their products. Microsoft recommends that customers contact their vendor if they have any questions whether or not a specific application is affected by this issue, and monitor for security updates released by these vendors.
• Protect Your Computer
We continue to encourage customers to follow our Protect Your Computer guidance of enabling a firewall, getting software updates and installing antivirus software. Customers can learn more about these steps by visiting Protect Your Computer.
For more information about staying safe on the Internet, visit Microsoft Security Central.
• Keep Windows updated
All Windows users should apply the latest Microsoft security updates to help make sure that their computers are as protected as possible. If you are not sure whether your software is up to date, visit Windows Update, scan your computer for available updates, and install any high-priority updates that are offered to you. If you have Automatic Updates enabled, the updates are delivered to you when they are released, but you have to make sure you install them.
I hope you find this information helpful. Remember to be careful what you click on.
