Pierluigi Paganini
April 11, 2018
AMD and Microsoft released the microcode and security updates for Spectre vulnerabilities.
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 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.
AMD released patches for Spectre Variant 2 attack that includes both microcode and operating system updates. AMD and Microsoft worked together to issue the updates on Tuesday.
“Today, AMD is providing updates regarding our recommended mitigations for Google Project Zero (GPZ) Variant 2 (Spectre) for Microsoft Windows users. These mitigations require a combination of processor microcode updates from our OEM and motherboard partners, as well as running the current and fully up-to-date version of Windows.” reads the announcement published by AMD. “For Linux users, AMD recommended mitigations for GPZ Variant 2 were made available to our Linux partners and have been released to distribution earlier this year.”
Microsoft initially released Spectre security patches for AMD-based systems in January, but it was forced to suspend them due to instability issues.
AMD experts highlighted that is quite difficult to exploit the Spectre Variant 2 on AMD chips, for this reason, it worked with partners to provide a combination of microcode and OS updates.
“While we believe it is difficult to exploit Variant 2 on AMD processors, we actively worked with our customers and partners to deploy the above described combination of operating system patches and microcode updates for AMD processors to further mitigate the risk,” continues the announcement.
AMD customers can install the microcode by downloading BIOS updates provided by manufacturers, while Windows 10 updates are included in the Microsoft April Patch Tuesday.
Windows 10 updates released by Microsoft on Tuesday include Spectre Variant 2 mitigationsfor AMD devices. According to AMD, the support for these mitigations for AMD processors in Windows Server 2016 is expected to be available following final validation and testing.
For Linux systems, AMD states that mitigations for GPZ Variant 2 were made available to its Linux partners and have been released to distribution earlier this year.
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(Security Affairs – Microsoft, Spectre)
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