A new software tool has been released by Linchpin Labs that allows the loading of unsigned and legacy drivers on Windows XP, 2003, and most importantly Vista.
One of the system management and control methods that Microsoft implemented with Windows Vista is requiring system drivers to be digitally signed before they will load properly within the system. If a user or administrator wishes to load an unsigned or legacy driver, they will either need to reboot into a limited functionality mode or just do without the functions that the driver would have provided.
As others have pointed out, this step will do nothing to prevent malware authors from being able to load their drivers into the system. Either they will exploit the lax jurisdiction and corporate oversight of various countries to establish a corporate shell and gain legitimate digitally signed driver certification, or they will just exploit weaknesses in already-signed drivers.
The process of digitally signing drivers risks becoming like that used to issue SSL certificates - only providing a moderate distraction for those with malicious intent on their way to obtaining accreditation, but a significant obstacle for the amateur developers without the necessary resources.
Into this environment, the developers at Linchpin Labs have released their Atsiv command line tool that allows for the loading of unsigned and legacy drivers into 32 and 64 bit versions of Windows XP, 2003, and Vista.
As the developers have acknowledged, this isn't the first tool to allow for the loading of unsigned drivers, but it is one of the first (if not the first) to use a signed system component to load an unsigned component.
To gain access to the full features of Atsiv, the user operating the tool is required to have Administrator privileges before starting the tool.
While Atsiv appears to be a top quality tool for the loading of unsigned drivers, it won't add the newly loaded driver to the standard drivers list, nor is it completely loaded into memory (for example, the DOS header is not loaded). This isn't necessary a drawback, depending on the intent of the person who is using it to load a driver.
Atsiv also ignores any dependencies that a driver might have, so it is necessary to ensure any dependencies are preloaded before attempting to load a driver that requires them. It also allows the same driver to be loaded multiple times in memory, potentially leading to interesting cases where multiple instances of a driver are fighting over the same information.
As with any other system modification and administration tool, system instability, failure or unresponsiveness may be encountered when using Atsiv - so use is at the user's own risk.
This article originally appeared at Sûnnet Beskerming
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Sûnnet Beskerming is an independent Information Security firm operating from the antipodes. Specialising in the gap between threat emergence and vendor response, Sûnnet Beskerming provides global reach with a local touch.