POS terminals: Improper Link Resolution Before File Access
CVE-2023-42137 is a high-severity improper link resolution before file access vulnerability in POS terminals from PAX Technology, 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 POS terminals versions: 11.1.50_20230614 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 0.47% 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 POS terminals you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| PAX Technology | POS terminals | 11.1.50_20230614 and earlier | Not stated |
| Paxtechnology | Paydroid | 8.1.0_sagittarius_11.1.50_20230614 and earlier | 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
- 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 | 7.8 | High | CNA (cert.pl) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
PAX Android based POS devices with PayDroid_8.1.0_Sagittarius_V11.1.50_20230614 or earlier can allow for command execution with high privileges by using malicious symlinks. The attacker must have shell access to the device in order to exploit this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Link Resolution Before File Access
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How developers prevent this class of flaw
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More Improper Link Resolution Before File Access vulnerabilities (CWE-59)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cert.pl/en/posts/2024/01/CVE-2023-4818/Third Party Advisory
- cert.pl/posts/2024/01/CVE-2023-4818/Third Party Advisory
Technical write-ups (may include proof of concept)
- blog.stmcyber.com/pax-pos-cves-2023/Exploit, Third Party Advisory
Other references
- ppn.paxengine.com/release/developmentPermissions Required
Other vulnerabilities in POS terminals
- 7.8 High severity
Recent Improper Link Resolution Before File Access vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 8.1 High severity
- 7.3 High severity
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