Elastic Ci Stack: Improper Link Resolution Before File Access
CVE-2023-43116 is a high-severity improper link resolution before file access vulnerability in Elastic Ci Stack from Buildkite, 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. The record lists versions 5.22.5, 6.7.1 as the first without the flaw, so updating Elastic Ci Stack to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.33% 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 Elastic Ci Stack to 5.22.5 or 6.7.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Buildkite | Elastic Ci Stack | before 5.22.5; 6.0.0 up to, but not including, 6.7.1 | 5.22.5, 6.7.1 |
Version data comes from NVD's product matching. 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.
Official description
A symbolic link following vulnerability in Buildkite Elastic CI for AWS versions prior to 6.7.1 and 5.22.5 allows the buildkite-agent user to change ownership of arbitrary directories via the PIPELINE_PATH variable in the fix-buildkite-agent-builds-permissions script.
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.
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- github.com/atredispartners/advisories/blob/master/ATREDIS-2023-0003.mdExploit, Third Party Advisory
Other vulnerabilities in Elastic Ci Stack
- 7.0 High severity
Recent Improper Link Resolution Before File Access vulnerabilities
- 8.1 High severity
- 7.3 High severity
- 7.8 High severity
- 7.5 High severity
- 8.1 High severity
- 7.3 High severity
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