Externally Controlled Reference to a Resource in Another Sphere Affecting kernel-tools-devel package, versions <0:4.14.304-226.531.amzn2


Severity

Recommended
high

Based on Amazon Linux security rating

    Threat Intelligence

    EPSS
    0.2% (59th percentile)

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  • Snyk ID SNYK-AMZN2-KERNELTOOLSDEVEL-5789073
  • published 20 Jul 2023
  • disclosed 25 Apr 2023

How to fix?

Upgrade Amazon-Linux:2 kernel-tools-devel to version 0:4.14.304-226.531.amzn2 or higher.
This issue was patched in ALAS2-2023-1932.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-tools-devel package and not the kernel-tools-devel package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

The current implementation of the prctl syscall does not issue an IBPB immediately during the syscall. The ib_prctl_set  function updates the Thread Information Flags (TIFs) for the task and updates the SPEC_CTRL MSR on the function __speculation_ctrl_update, but the IBPB is only issued on the next schedule, when the TIF bits are checked. This leaves the victim vulnerable to values already injected on the BTB, prior to the prctl syscall.  The patch that added the support for the conditional mitigation via prctl (ib_prctl_set) dates back to the kernel 4.9.176.

We recommend upgrading past commit a664ec9158eeddd75121d39c9a0758016097fa96

CVSS Scores

version 3.1
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NVD

7.5 high
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    None
  • Availability (A)
    None
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Red Hat

4.7 medium
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SUSE

4.7 medium