CVE-2023-31421
It was discovered that when acting as TLS clients, Beats, Elastic Agent, APM Server, and Fleet Server did not verify whether the server certificate is valid for the target IP address; however, certificate signature validation is still performed.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
It was discovered that when acting as TLS clients, Beats, Elastic Agent, APM Server, and Fleet Server did not verify whether the server certificate is valid for the target IP address; however, certificate signature validation is still performed. More specifically, when the client is configured to connect to an IP address (instead of a hostname) it does not validate the server certificate's IP SAN values against that IP address and certificate validation fails, and therefore the connection is not blocked as expected.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.27% probability · 19th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295
- Affected
- elastic/elastic beats · elastic/elastic agent · elastic/apm server · elastic/elastic fleet server
- Source
- security@elastic.co
References
- https://discuss.elastic.co/t/beats-elastic-agent-apm-server-and-fleet-server-8-10-1-security-update-improper-certificate-validation-issue-esa-2023-16/343385Vendor Advisory
- https://www.elastic.co/community/securityVendor Advisory
- https://discuss.elastic.co/t/beats-elastic-agent-apm-server-and-fleet-server-8-10-1-security-update-improper-certificate-validation-issue-esa-2023-16/343385Vendor Advisory
- https://www.elastic.co/community/securityVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.