Arm patches Mali GPU driver bug exploited by spyware

Commercial spyware has exploited a security hole in Arm’s Mali GPU drivers to compromise some people’s devices, according to Google today.

These graphics processors are used in a ton of gear, from phones and tablets to laptops and cars, so the kernel-level vulnerability may be present in countless equipment. This includes Android handsets made by Google, Samsung, and others.

The vulnerable drivers are paired with Arm’s Midgard (launched in 2010), Bifrost (2016), Valhall (2019), and fifth generation Mali GPUs (2023), so we imagine this buggy code will be in millions of systems.

On Monday, Arm issued an advisory for the flaw, which is tracked as CVE-2023-4211. This is a use-after-free bug affecting Midgard driver versions r12p0 to r32p0; Bifrost versions r0p0 to r42p0; Valhall versions r19p0 to r42p0; and Arm 5th Gen GPU Architecture versions r41p0 to r42p0.

We’re told Arm has corrected the security blunder in its drivers for Bifrost to fifth-gen. “This issue is fixed in Bifrost, Valhall, and Arm 5th Gen GPU Architecture Kernel Driver r43p0,” the advisory stated. “Users are recommended to upgrade if they are impacted by this issue. Please contact Arm support for Midgard GPUs.”

We note version r43p0 of Arm’s open source Mali drivers for Bifrost to fifth-gen were released in March. Midgard has yet to publicly get that version, it appears, hence why you need to contact Arm for that. We’ve asked Arm for more details on that.

What this means for the vast majority of people is: look out for operating system or manufacturer updates with Mali GPU driver fixes to install to close this security hole, or look up the open source drivers and apply updates yourself if you’re into that. Your equipment may already be patched by now, given the release in late March, and details of the bug are only just coming out. If you’re a device maker, you should be rolling out patches to customers.

“A local non-privileged user can make improper GPU memory processing operations to gain access to already freed memory,” is how Arm described the bug. That, it seems, is enough to allow spyware to take hold of a targeted vulnerable device.

According to Arm there is “evidence that this vulnerability may be under limited, targeted exploitation.” We’ve received confirmation from Google, whose Threat Analysis Group’s (TAG) Maddie Stone and Google Project Zero’s Jann Horn found and reported the vulnerability to the chip designer, that this targeted exploitation has indeed taken place.

“At this time, TAG can confirm the CVE was used in the wild by a commercial surveillance vendor,” a TAG spokesperson told The Register. “More technical details will be available at a later date, aligning with our vulnerability disclosure policy.”



Source: Arm patches Mali GPU driver bug exploited by spyware • The Register

Robin Edgar

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