CyberSecBulletin
CVE-2022-30283NVD status: Modified

Kernel: Time-of-check Time-of-use (TOCTOU) Race Condition

Published Updated By the CyberSecBulletin desk

CVE-2022-30283 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in Kernel from Insyde, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited with local access to the system by an attacker with administrator privileges, without any action from a user. The record lists versions 5.0.05.09.21, 5.1.05.17.21, 5.2.05.27.21 as the first without the flaw, so updating Kernel to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Kernel to 5.0.05.09.21 or 5.1.05.17.21 or 5.2.05.27.21 or 5.3.05.36.21, whichever matches your release line, or a later version.
  2. Read the advisory on insyde.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
InsydeKernel5.0 up to, but not including, 5.0.05.09.21; 5.1 up to, but not including, 5.1.05.17.21; 5.2 up to, but not including, 5.2.05.27.21; 5.3 up to, but not including, 5.3.05.36.21; 5.4 up to, but not including, 5.4.05.44.21; 5.5 up to, but not including, 5.5.05.52.215.0.05.09.21, 5.1.05.17.21, 5.2.05.27.21, 5.3.05.36.21, 5.4.05.44.21, 5.5.05.52.21

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighNVD
CVSS 3.17.5HighCISA (ADP)

Official description

In UsbCoreDxe, tampering with the contents of the USB working buffer using DMA while certain USB transactions are in process leads to a TOCTOU problem that could be used by an attacker to cause SMRAM corruption and escalation of privileges The UsbCoreDxe module creates a working buffer for USB transactions outside of SMRAM. The code which uses can be inside of SMM, making the working buffer untrusted input. The buffer can be corrupted by DMA transfers. The SMM code code attempts to sanitize pointers to ensure all pointers refer to the working buffer, but when a pointer is not found in the list of pointers to sanitize, the current action is not aborted, leading to undefined behavior. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group. Fixed in: Kernel 5.0: Version 05.09. 21 Kernel 5.1: Version 05.17.21 Kernel 5.2: Version 05.27.21 Kernel 5.3: Version 05.36.21 Kernel 5.4: Version 05.44.21 Kernel 5.5: Version 05.52.21 https://www.insyde.com/security-pledge/SA-2022063

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How developers prevent this class of flaw

  • The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
  • When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
  • Limit the interleaving of operations on files from multiple processes.

More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Kernel

All Kernel vulnerabilities

Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities

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