CPG BIOS: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2022-34398 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in CPG BIOS from Dell, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected CPG BIOS versions: 2.15.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Alienware Area 51m R1 Firmware to 1.22.2 or a later version.
- Update Alienware Area 51m R2 Firmware to 1.19.0 or a later version.
- Update Alienware Aurora R10 Firmware to 2.3.2 or a later version.
- Read the advisory on dell.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- 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:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (emc.com) |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
Dell BIOS contains a Time-of-check Time-of-use vulnerability. A local authenticated malicious user could\u00a0potentially exploit this vulnerability by using a specifically timed DMA transaction during an SMI to gain arbitrary code execution on the system.
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
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in CPG BIOS
- 8.2 High severity
- 8.2 High severity
- 8.2 High severity
- 7.6 High severity
- 7.8 High severity
Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 7.1 High severity
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