BIOS: Incorrect Default Permissions
CVE-2022-3431 is a high-severity incorrect default permissions vulnerability in BIOS from Lenovo, with a CVSS 3.1 base score of 7.8 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 BIOS versions: various. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.21% 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 Ideapad Creator 5-16ach6 Firmware to gscn34ww or a later version.
- Update Ideapad 5 Pro-16ihu6 Firmware to grcn22ww or a later version.
- Update Ideapad 5 Pro-16ach6 Firmware to gscn34ww or a later version.
- Read the advisory on support.lenovo.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 2 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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.7 | Medium | CNA (lenovo.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A potential vulnerability in a driver used during manufacturing process on some consumer Lenovo Notebook devices that was mistakenly not deactivated may allow an attacker with elevated privileges to modify secure boot setting by modifying an NVRAM variable.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.
How developers prevent this class of flaw
- The architecture needs to access and modification attributes for files to only those users who actually require those actions.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
More Incorrect Default Permissions vulnerabilities (CWE-276)
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
Other vulnerabilities in BIOS
- 7.8 High severity
- 7.8 High severity
Recent Incorrect Default Permissions vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
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