libiec61850: Improper Limitation of a Pathname to a Restricted Directory
CVE-2022-3976 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in libiec61850 from MZ Automation, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected libiec61850 versions: 1.0; 1.1; 1.2, 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 0.53% 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 libiec61850 you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MZ Automation | libiec61850 | 1.0; 1.1; 1.2; 1.3; 1.4 | 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
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A vulnerability has been found in MZ Automation libiec61850 up to 1.4 and classified as critical. This vulnerability affects unknown code of the file src/mms/iso_mms/client/mms_client_files.c of the component MMS File Services. The manipulation of the argument filename leads to path traversal. Upgrading to version 1.5 is able to address this issue. The name of the patch is 10622ba36bb3910c151348f1569f039ecdd8786f. It is recommended to upgrade the affected component. The identifier of this vulnerability is VDB-213556.
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
Third-party and government advisories
- github.com/mz-automation/libiec61850Third Party Advisory
- vuldb.com/?id.213556Third Party Advisory
Other vulnerabilities in libiec61850
- 8.2 High severity
- 8.7 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.5 High severity
- 7.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
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