Security Bugs in Video Chat Tools Enable Remote Attackers

Newly discovered security bugs in Lifesize videoconferencing products can be remotely exploited, giving attackers the ability to spy on a target organization or attack other devices.

Trustwave SpiderLabs security researcher Simon Kenin found the remote OS command injection vulnerabilities, which affect Lifesize Team, Lifesize Room, Lifesize Passport, and Lifesize Networker. Lifesize has a range of major clients – eBay, PayPal, and Netflix among them.

Exploitation of these flaws can give adversaries access to the products' firmware. Kenin called the bug "trivial," but it requires some hard-to-get information: Remote hackers will need the firmware code for their target devices, which can only be downloaded from the Lifesize website with a valid serial number for the specific product in mind. But firmware code isn't necessary for attackers with physical device access, says Trustwave threat intelligence manager Karl Sigler.

These bugs affect the Lifesize support page, where users can troubleshoot issues and send log files for their devices. Attackers must log in to the support interface, which often isn't difficult because many owners fail to change the default credentials that ship with Lifesize products.

"The vulnerability itself is in how they implement PHP in the Web interface to the devices," Sigler explains in an interview with Dark Reading. "Unfortunately, the PHP code is pretty poor in how it's implemented ... you can basically execute any command you want on the device using that interface."

It's a "classic programming error," Kenin wrote in a blog post on the findings. User input is passed without any sanitization to the PHP shell_exec function, which executes system commands as the Web server user. With no limit on the type of code that can be passed, attackers who know how to pass arguments to a PHP page can launch any commands they want.

With this vulnerability alone, intruders could gain a foothold on the network and execute commands on the target device to probe other machines on the network. But they also could achieve full persistence on the device with an unpatched privilege escalation bug, which was discovered in 2016 and affects the same pool of devices, Sigler says. The duo would give someone full control of the appliance, access to media, as well as access to other devices.

A Patch is En Route
Trustwave contacted Lifesize in November to begin the disclosure process, did not receive a response, and then re-established contact last month. Lifesize initially said it would not be releasing a patch because the affected devices were legacy and had end-of-life and end-of-sale dates.

It has since changed its position and will be offering a patch. In the meantime, customers using Lifesize 220 systems should contact support for a hotfix. There is no evidence the bugs have been exploited in the wild, says Sigler, and Trustwave promptly reached out to Lifesize so it could create a patch before someone takes advantage of the flaw.

"If we can find it, criminals can, too," he notes.

For companies that decide to abandon support for their legacy systems, Sigler urges making customers aware at least one year ahead of time so they can pursue upgrade or replacement options. They should also make upgrade options available so users understand the risk they're taking on by continuing to use legacy products. 

Trustwave is holding off on its release of the proof-of-concept for these vulnerabilities so users can apply the hotfix. Researcher plan to publish the PoC on Feb. 21, 2019. "At that time, we will release the PoC code to provide users, administrators, and network security professionals with the technical details and tools to validate whether they are still vulnerable," Sigler says.

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