Menu
Utility evades Vista kernel defences

Utility evades Vista kernel defences

A security feature in the 64-bit version of Windows Vista can be easily circumvented with a free utility that loads unsigned drivers into the kernel, according to researchers at Symantec.

Among 64-bit Vista's security provisions is one new to Microsoft's operating systems: only digitally-signed code can be loaded into the kernel. Under those new rules, code destined for the kernel -- typically drivers -- must be accompanied by a signed certificate available from a limited number of issuing authorities. Drivers not equipped with a legitimate certificate aren't loaded.

The thinking behind the move was that it would stymie rootkits, which load driver code into the kernel as part of their cloaking tactics.

But a pair of Symantec security researchers pointed to a free utility from Australian developer LinchpinLabs as one easy end-around. LinchpinLabs' Atsiv, said Ollie Whitehouse, an architect with Symantec's advanced threats research team, uses signed drivers to load other, unsigned code, into the Vista kernel.

"[Atsiv's] command line tool loads [its own] appropriate driver, which then in turn allows loading of unsigned drivers due to the implementation of their PE loader," said Whitehouse. "A side effect of using their own load is noted by the authors in their design documentation: 'Atsiv doesn't add the driver to the PsLoadedModuleslist so it is not visible in the standard drivers list.'

"This is rootkit-type behavior," said Whitehouse.

One of LinchpinLabs' developers, identified only as "Dan," argued on rootkit.com that Vista's signing requirement "doesn't prevent malware, it just prohibits freedom to choose." Dan also claimed that Microsoft could never prevent hackers from obtaining legitimate certificates.

"A signed file uniquely identifies the company that developed that file, but when companies can be created and registered in jurisdictions known for protecting the privacy of company founders and directors you have to ask what does driver signing actually represent?" Dan asked. "While driver signing certificates can be revoked, new certificates, with enough money, can be created faster than it takes to change a file's signature. If this is indeed the case, then it is the hobbyists and home user that end up paying the cost."

Whitehouse agreed that the only way Microsoft can enforce the ban on unsigned kernel code is to revoke the certificate. "It'll be interesting to see how long it takes Microsoft to do this," Whitehouse said. "Secondly, as [Dan] points out, all it will take is someone to register another company, obtain another signing certificate, and the process will start over again."

Symantec, McAfee and others argued that they needed to inject their own code into the kernel in order to protect users from the stealthiest kinds of malware.

Microsoft did not immediately reply to questions about whether it would revoke the certificate used by Atsiv.


Follow Us

Join the newsletter!

Or
Error: Please check your email address.

Tags vistasymantec

Featured

Slideshows

Bumper channel crowd kicks off first After Hours of 2018

Bumper channel crowd kicks off first After Hours of 2018

After Hours made a welcome return to the channel social calendar with a bumper crowd of partners, distributors and vendors descending on The Jefferson in Auckland to kick-start 2018. Photos by Gino Demeer.

Bumper channel crowd kicks off first After Hours of 2018
Looking back at the top 15 M&A deals in NZ during 2017

Looking back at the top 15 M&A deals in NZ during 2017

In 2017, merger and acquisitions fever reached new heights in New Zealand, with a host of big name deals dominating the headlines. Reseller News recaps the most important transactions of the Kiwi channel during the past 12 months.

Looking back at the top 15 M&A deals in NZ during 2017
Kiwi channel closes 2017 with After Hours

Kiwi channel closes 2017 with After Hours

The channel in New Zealand came together to celebrate the close of 2017, as the final After Hours played out in front of a bumper Auckland crowd.

Kiwi channel closes 2017 with After Hours
Show Comments