c-ares: Uncontrolled Resource Consumption
CVE-2023-32067 is a high-severity uncontrolled resource consumption vulnerability in c-ares, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.19.1 as the first without the flaw, so updating c-ares to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.58% chance of exploitation within 30 days, higher than 76% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update c-ares to 1.19.1 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| C-ares | c-ares | < 1.19.1; before 1.19.1 | 1.19.1 |
| Fedora Project | fedora | 37; 38 | Not stated |
| Debian | debian_linux | 10.0; 11.0 | 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
- NetworkCan be exploited remotely over a network, including the internet.
- 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
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
c-ares is an asynchronous resolver library. c-ares is vulnerable to denial of service. If a target resolver sends a query, the attacker forges a malformed UDP packet with a length of 0 and returns them to the target resolver. The target resolver erroneously interprets the 0 length as a graceful shutdown of the connection. This issue has been patched in version 1.19.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How developers prevent this class of flaw
- Ensure that protocols have specific limits of scale placed on them.
- Ensure that all failures in resource allocation place the system into a safe posture.
More Uncontrolled Resource Consumption vulnerabilities (CWE-400)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/c-ares/c-ares/security/advisories/GHSA-9g78-jv2r-p7vcThird Party Advisory
Patches and release notes
- github.com/c-ares/c-ares/releases/tag/cares-1_19_1Release Notes
Third-party and government advisories
- lists.fedoraproject.org/archives/list/[email protected]/message/B5Z5XFNXTNPTCBBVXFDNZQ…Mailing List, Third Party Advisory
- lists.fedoraproject.org/archives/list/[email protected]/message/UBFWILTA33LOSV23P44FGT…Mailing List, Third Party Advisory
- security.gentoo.org/glsa/202310-09Third Party Advisory
- debian.org/security/2023/dsa-5419Third Party Advisory
Other references
Other vulnerabilities in c-ares
- 7.5 High severity
- 7.5 High severity
- 8.3 High severity
- 8.6 High severity
Recent Uncontrolled Resource Consumption vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
Spotted an error? Tell us.