UBI Reader: Improper Limitation of a Pathname to a Restricted Directory
CVE-2022-4572 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in UBI Reader, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected UBI Reader versions: 0.1; 0.2; 0.3, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.58% 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
- Check which version of UBI Reader you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| UBI Reader | UBI Reader | 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8 | Not stated |
Version data comes from the organisation that assigned the CVE. 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
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- 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:N/UI:R/S:U/C:N/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.4 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.1 | High | NVD |
Official description
A vulnerability, which was classified as problematic, has been found in UBI Reader up to 0.8.0. Affected by this issue is the function ubireader_extract_files of the file ubireader/ubifs/output.py of the component UBIFS File Handler. The manipulation leads to path traversal. The attack may be launched remotely. Upgrading to version 0.8.5 is able to address this issue. The name of the patch is d5d68e6b1b9f7070c29df5f67fc060f579ae9139. It is recommended to upgrade the affected component. VDB-216146 is the identifier assigned to this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/jrspruitt/ubi_reader/commit/d5d68e6b1b9f7070c29df5f67fc060f579ae9139Third Party Advisory
- github.com/jrspruitt/ubi_reader/pull/57Issue Tracking, Third Party Advisory
- github.com/jrspruitt/ubi_reader/releases/tag/v0.8.5-masterRelease Notes, Third Party Advisory
Third-party and government advisories
- vuldb.com/?id.216146Third Party Advisory
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
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