Security News > 2021 > March > New Bugs Could Let Hackers Bypass Spectre Attack Mitigations On Linux Systems

Cybersecurity researchers on Monday disclosed two new vulnerabilities in Linux-based operating systems that, if successfully exploited, could let attackers circumvent mitigations for speculative attacks such as Spectre and obtain sensitive information from kernel memory.

While CVE-2020-27170 can be abused to reveal content from any location within the kernel memory, CVE-2020-27171 can be used to retrieve data from a 4GB range of kernel memory.

First documented in January 2018, Spectre and Meltdown take advantage of flaws in modern processors to leak data that are currently processed on the computer, thereby allowing a bad actor to bypass boundaries enforced by the hardware between two programs to get hold of cryptographic keys.

The new vulnerabilities uncovered by Symantec aim to get around these mitigations in Linux by taking advantage of the kernel's support for extended Berkeley Packet Filters to extract the contents of the kernel memory.

"Unprivileged BPF programs running on affected systems could bypass the Spectre mitigations and execute speculatively out-of-bounds loads with no restrictions," Symantec said.

Specifically, the kernel was found to perform undesirable out-of-bounds speculation on pointer arithmetic, thus defeating fixes for Spectre and opening the door for side-channel attacks.

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