chromebook-bug-could-reveal-location-history-from-guest-mode

Chromebook bug could reveal location history from Guest mode

A little-known behavior in Chrome OS could reveal a user’s movements through Wi-Fi logs. Leveraging Chrome OS’s Guest mode feature, the attack would require physical access to the device, but it can be executed without knowing the user’s password or having login access.

The bug was flagged to The Verge by the Committee on Liberatory Information Technology, a tech collective that includes several former Googlers.

“We are looking into this issue,” said a Google spokesperson. “In the meantime, device owners can turn off guest mode and disable the creation of new users.” Instructions for turning off Guest browsing are available here.

The bug stems from the way Chromebooks treat their Wi-Fi logs, which show when and how a computer connects to the broader internet. The logs can be confusing for nontechnical users, but they can be deciphered to reveal which Wi-Fi networks were in range of the computer. Combined with other available data, that could reveal the owner’s movements over the period of time covered by the logs — potentially as long as seven days.

Because Chrome OS keeps those logs in unprotected memory, they can be accessed without a password. Simply opening a Chromebook in Guest mode and navigating to a standardized address will bring up the logs in local storage. That will show all logs for the computer, even ones generated outside of Guest mode.

Electronic Frontier Foundation researcher Andrés Arrieta confirmed the attack and said it was of particular concern for targeted and marginalized communities. While the bug wouldn’t be useful to conventional cybercriminals, it’s a potentially devastating privacy issue for those worried about surveillance from family members or co-workers.

“It’s worrisome because anyone with quick physical access to the device could potentially get in as guest and quickly take some logs, and out details of location,” said Arrieta. “Security teams should try to better understand the potential repercussions of those bugs for all their users and include that in their assessment and prioritization of bugs.”

amd’s-radeon-rx-6600-xt-will-land-with-just-32mb-of-infinity-cache

AMD’s Radeon RX 6600 XT Will Land With Just 32MB of Infinity Cache

(Image credit: AMD)

AMD (via Kepler_L2) released a new Linux patch that exposes the cache configuration for its Navi 21, Navi 22 and Navi 23 silicon. The last is rumored to power the chipmaker’s upcoming Radeon RX 6600 series (or maybe RX 6500 series).

The description for the patch reads: “The L1 cache information has been updated and the L2/L3 information has been added. The changes have been made for Vega10 and newer ASICs. There are no changes for the older ASICs before Vega10.” Therefore, it holds a ton of valuable information on both existing and future AMD products.

Introduced with RDNA 2, Infinity Cache basically acts as a big L3 cache that’s accessible by the GPU. It’s there to help improve performance since AMD’s RDNA 2 graphics cards employ relatively narrow memory interfaces. The Radeon RX 6800 XT for example uses a 256-bit bus, but manages to mostly keep pace with the GeForce RTX 3080’s 320-bit bus that also includes higher clocked GDDR6X memory.

Navi 21 (Sienna Cichlid) and Navi 22 (Navy Flounder) sport 128MB and 96MB of Infinity Cache, respectively. According to the new information, Navi 23 will wield 32MB of Infinity Cache. In comparison to Navi 22, we’re looking at a 66.7% reduction on Navi 23. That should also help cut down the die size, though at the cost of performance.

AMD Navi 23 (Image credit: Freedesktop)

The jury is still out on whether AMD will use Navi 23 for the Radeon RX 6600 series, though. Some think that Navi 23 could find its way into the Radeon RX 6500 series instead. Regardless, AIDA64, a popular monitoring and diagnostics tool, recently received support for Radeon RX 6600 series. Assuming that the software’s release notes are accurate, the Radeon RX 6600 XT and RX 6600 will indeed be based around the Navi 23 die.

ASRock registered a couple of Radeon RX 6600 XT models with the Eurasian Economic Commission (EEC) not so long ago. It’s important to highlight that not every product makes it to the market, but if what ASRock submitted is true, the Radeon RX 6600 XT may feature 12GB of GDDR6 memory. Realistically, it makes more sense for the Radeon RX 6600 XT to have 8GB of GDDR6 memory across a 128-bit memory interface.

The fact that AIDA64 already supports the Radeon RX 6600 series hints that a potential launch may not be too far around the corner. We’re still waiting for a trimmed down Radeon RX 6700 using Navi 22, which we expect to see some time in April.