Google tells users of some Android phones: Nuke voice calling to avoid infection


Enlarge / Photos of the Samsung Galaxy S21, which runs with an Exynos chipset.


Google is urging house owners of sure Android telephones to take pressing motion to guard themselves from vital vulnerabilities that give expert hackers the power to surreptitiously compromise their units by making a specifically crafted name to their quantity.  It’s not clear if all actions urged are even potential, nonetheless, and even when they’re, the measures will neuter units of most voice-calling capabilities.

The vulnerability impacts Android units that use the Exynos chipset made by Samsung’s semiconductor division. Weak units embody the Pixel 6 and seven, worldwide variations of the Samsung Galaxy S22, varied mid-range Samsung telephones, the Galaxy Watch 4 and 5, and vehicles with the Exynos Auto T5123 chip. These units are ONLY susceptible in the event that they run the Exynos chipset, which incorporates the baseband that processes indicators for voice calls. The US model of the Galaxy S22 runs a Qualcomm Snapdragon chip.

A bug tracked as CVE-2023-24033 and three others which have but to obtain a CVE designation make it potential for hackers to execute malicious code, Google’s Mission Zero vulnerability staff reported on Thursday. Code-execution bugs within the baseband might be particularly vital as a result of the chips are endowed with root-level system privileges to make sure voice calls work reliably.

“Assessments carried out by Mission Zero verify that these 4 vulnerabilities permit an attacker to remotely compromise a telephone on the baseband stage with no person interplay, and require solely that the attacker know the sufferer’s telephone quantity,” Mission Zero’s Tim Willis wrote. “With restricted extra analysis and improvement, we imagine that expert attackers would be capable of shortly create an operational exploit to compromise affected units silently and remotely.”

Earlier this month, Google launched a patch for susceptible Pixel fashions. Samsung has launched an replace patching CVE-2023-24033, but it surely has not yet been delivered to finish customers. There’s no indication Samsung has issued patches for the opposite three vital vulnerabilities. Till susceptible units are patched, they continue to be susceptible to assaults that give entry on the deepest stage potential.

The menace prompted Willis to place this recommendation on the very prime of Thursday’s submit:

Till safety updates can be found, customers who want to shield themselves from the baseband distant code execution vulnerabilities in Samsung’s Exynos chipsets can flip off Wi-Fi calling and Voice-over-LTE (VoLTE) of their system settings. Turning off these settings will take away the exploitation threat of those vulnerabilities.

The issue is, it’s not fully clear that it’s potential to show off VoLTE, no less than on many fashions. A screenshot one S22 person posted to Reddit final 12 months reveals that the choice to show off VoLTE is grayed out. Whereas that person’s S22 was working a Snapdragon chip, the expertise for customers of Exynos-based telephones is probably going the identical.

And even whether it is potential to show off VoLTE, doing so along with turning off Wi-Fi could flip telephones into little greater than tiny tablets working Android. VoLTE got here into widespread use just a few years in the past, and since then most carriers in North America have stopped supporting older 3G and 2G frequencies.

Samsung representatives mentioned in an e-mail that the corporate in March launched safety patches for 5 of six vulnerabilities that “could probably affect choose Galaxy units” and can patch the sixth flaw subsequent month. The e-mail didn’t reply questions asking if any of the patches can be found to finish customers now or whether or not it’s potential to show off VoLTE.

A Google consultant, in the meantime, declined to supply the particular steps for finishing up the recommendation within the Mission Zero writeup. Readers who work out a method are invited to clarify the method (with screenshots, if potential) within the feedback part.

Due to the severity of the bugs and the benefit of exploitation by expert hackers, Thursday’s submit omitted technical particulars. In its product security update page, Samsung described CVE-2023-24033 as a “reminiscence corruption when processing SDP attribute accept-type.”

“The baseband software program doesn’t correctly test the format varieties of accept-type attribute specified by the SDP, which might result in a denial of service or code execution in Samsung Baseband Modem,” the advisory added. “Customers can disable WiFi calling and VoLTE to mitigate the affect of this vulnerability.”

Quick for the Service Discovery Protocol layer, SDP permits for the invention of providers accessible from different units over Bluetooth. In addition to discovery, SDP permits functions to find out the technical traits of these providers. SDP makes use of a request/response mannequin for units to speak.

The menace is critical, however as soon as once more, it applies solely to individuals utilizing an Exynos model of one of many affected fashions. And as soon as once more, Google issued a patch earlier this month for Pixel customers.

Till Samsung or Google says extra, customers of units that stay susceptible ought to (1) set up all accessible safety updates with an in depth eye out for one patching CVE-2023-24033, (2) flip off Wi-Fi calling, and (3) discover the settings menu of their particular mannequin to see if it’s potential to show off VoLTE. This submit will probably be up to date if both firm responds with extra helpful data.