New Tool Dusts for Fingerprints

A 'fingerprinting' tool that cracks device drivers will go public soon

This is the sort of fingerprint analysis you don't want to see used in your enterprise.

Jon Ellch, an independent researcher and graduate student, next month will release a Unix-based 802.11 "fingerprinting tool" that can be used to launch an attack via device drivers. (See Device Drivers at Risk.)

Ellch will make the software available after demonstrating exploits he created with it at the Black Hat and Defcon conferences in Las Vegas next month. Ellch and David Maynor, senior security researcher for SecureWorks, will give a presentation on device-driver vulnerabilities on August 2 at Black Hat.

The two researchers contend that hacking into a device driver isn't rocket science and that these exploits aren't limited to 802.11 WLANs, but can occur in wired LANs, too.

Knowing crucial details of a device driver, such as its version and chipset, is key to a successful attack. Ellch's fingerprinting tool grabs that information. "Knowing the driver is useful, but knowing the version is even more useful," says Ellch, whose research started out mainly on 802.11 WLAN devices. "If I know the version of the driver, I can tune my exploit so it's more reliable."

With the new tool, an attacker can remotely tell not only how many people in a room have Intel and Broadcom chipsets in their laptops, but what versions of the device-driver software they are running, Ellch says. "If you didn't know which version it was, you might own three or four of the ten people and could crash their systems. But [with the tool], you could [own] all ten instead."

Device drivers usually aren't secured and can run with the highest operating system privileges, making the new exploit potentially hazardous to enterprise IT health. But like any proof of concept, Ellch's research can potentially help the good guys, too.

Dino Dai Zovi, security researcher at Matasano Security and author of the Karma wireless security tool, envisions this fingerprinting feature as a way for enterprises to remotely track whether wireless devices are running up-to-date operating system and device driver programs. "These [device drivers] are not typically updated for security vulnerabilities," Dai Zovi says. "For example, wireless IDS vendors may use this to passively detect vulnerable devices and alert network administrators."

The new tool could also be used to scan wireless devices so that only patched and legit ones can access the network, he says.

Ellch has a similar vision for his invention. Fingerprinting could help an enterprise ensure that users logging on to their WLAN are using corporate-issue laptops, rather than their own. "If you took a fingerprint of a laptop and set up a WLAN to fingerprint it on the fly as you connect, it would filter out" unauthorized laptops, he says. But he admits a smart attacker could still spoof a legit laptop, so fingerprinting isn't foolproof.

Meanwhile, Ellch says he's polishing up his fingerprinting tool's user interface, which currently is "a little rough." He says he'll probably release the tool as part of his already available 802.11 suite of "cracker" tools. And he and Maynor are in the throes of devising some other exploits they'll demo at Black Hat. "We're just banging on some more bugs to see what we can get," he says.

— Kelly Jackson Higgins, Senior Editor, Dark Reading

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