AMD Zen 2 CPUs Security Flaw Exposes Passwords, Encryption Keys
The vulnerability, called ‘Zenbleed,’ is said to impact all Zen 2 CPUs, including those in the Ryzen 3000 and 4000 series, as well as Epyc “Rome” processors.
Through the exploitation of Zenbleed, malicious actors can extract protected information, such as passwords and encryption keys, from affected PCs, according to Ormandy.
The vulnerability stems from a flaw in the register file of the CPUs, responsible for storing data needed to execute operations.
By manipulating the register files to force a mispredicted command, hackers can eavesdrop on essential system operations, making it possible to spy on the chip’s activities even within virtual machines, sandboxes, or containers.
While not easy to execute, Ormandy’s research shows that it is possible to leak around 30 kb of data per core per second, allowing the monitoring of encryption keys and passwords during user logins.
Ormandy responsibly reported the issue to AMD in May. However, the company has indicated that it will take several months to develop and release the necessary patches.
According to AMD’s security bulletin, the fix for most Ryzen processors on desktops and laptops is expected to be available in December, while the Ryzen Threadripper 3000 series should receive the patch in October.
One concern with the upcoming patches is the potential performance decrease they may cause. Users can anticipate the fixes to arrive through updates provided by their motherboard manufacturer or PC system maker.
AMD has also assured users that a microcode patch update for Zen 2 AMD EPYC products is already available, whereas further mitigations will be made available through BIOS updates later this year.