Pierluigi Paganini March 22, 2018

Google announced that mitigations for devices with Intel processors that are affected by the Spectre and Meltdown vulnerabilities will be available for latest stable channel update for Google’s Chrome OS operating system.

The Meltdown and Spectre attacks could be exploited by attackers to bypass memory isolation mechanisms and access target sensitive data.

The Meltdown attack could allow attackers to read the entire physical memory of the target machines stealing credentials, personal information, and more.

The Meltdown exploits the speculative execution to breach the isolation between user applications and the operating system, in this way any application can access all system memory.

The Spectre attack allows user-mode applications to extract information from other processes running on the same system. It can also be exploited to extract information from its own process via code, for example, a malicious JavaScript can be used to extract login cookies for other sites from the browser’s memory.

The Spectre attack breaks the isolation between different applications, allowing to leak information from the kernel to user programs, as well as from virtualization hypervisors to guest systems.

Meltdown attacks trigger the CVE-2017-5754 vulnerability, while Spectre attacks the CVE-2017-5753 (Variant 1) and CVE-2017-5715 (Variant 2). According to the experts, only Meltdown and Spectre Variant 1 can be addressed via software, while Spectre Variant 2 required an update of the microcode for the affected processors. Software mitigations include.

Google addressed the Meltdown issue in Chrome OS with the release of the version 63 in December, tens of days before researchers at Google Project Zero disclosure the flaws.

Google rolled out the KPTI/KAISER patch to address the flaw in 70 Intel-based Chromebook models from various vendors, including Acer, ASUS, Dell, HP, Lenovo, and Samsung.

This week the company released Chrome OS 65 release that also includes the KPTI mitigation against Meltdown for a number of Intel-based systems that were not addressed in with version 3.14 of the kernel.

According to Google, all older Chromebooks with Intel processors should get the KPTI mitigation for Meltdown with the release of Chrome OS 66 that is scheduled for release on April 24.

“The Stable channel has been updated to 65.0.3325.167 (Platform version: 10323.58.0/1) for most Chrome OS devices. This build contains a number of bug fixes and security updates.” reads the Google announcement.

“Intel devices on 3.14 kernels received the KPTI mitigation against Meltdown with Chrome OS 65.

All Intel devices received the Retpoline mitigation against Spectre variant 2 with Chrome OS 65.”

Chrome OS 65 also includes the Retpoline mitigation for Spectre Variant 2 for all Intel-based devices. Google experts highlighted that for Spectre Variant 1 attack, hackers can abuse the eBPF feature in the Linux kernel, but Chrome OS disables eBPF.

Chrome OS devices running on ARM-based systems are not affected by Meltdown. Google is working to cover also Spectre issues.

“On ARM devices we’ve started integrating firmware and kernel patches supplied by ARM. Development is still ongoing so release timelines have not been finalized. ARM devices will receive updated firmware and kernels before they enable virtualization features.” concluded Google.

Pierluigi Paganini

(Security Affairs – Chrome OS, Meltdown and Spectre)

[adrotate banner=”5″]

[adrotate banner=”13″]