Cortex Xpanse identifies Inferred CVEs by matching the service version information available to our scanners with CVE information from the NVD.
Common Vulnerabilities and Exposures (CVE) is a system for referencing publicly disclosed software security vulnerabilities. Individual vulnerabilities are commonly referred to as CVEs, and each one is uniquely identified by a CVE ID, such as CVE-2020-1234.
Cortex Xpanse attempts to match each service with CVEs that might be present on that service. We refer to any potential matches as Inferred CVEs. We perform this matching using the service name and version information that is available to our scanners.
We categorize Inferred CVE matches as High or Medium Confidence based on the version information that is available on the service and from the National Vulnerability Database (NVD).
High Confidence—Precise version information is available both from the service and from NVD.
Medium Confidence—Part of the version information from the service matches the NVD entry for the CVE, but the version information from the service has additional characters
The table below provides examples of Inferred CVE matches.
Service information available from Xpanse Scan | CVE information available from NVD | Match Result | Details |
|---|---|---|---|
Apache v 2.4.50 | CVE-2021-41773 Affects cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:* | No Match | Because the CPE information from NVD indicates a version of Apache that is different than the one we saw in the scan, this does not match. |
Apache v 2.4.49 | CVE-2021-41773 Affects cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:* | High Confidence Match | Because the CPE information from NVD matches the version of Apache indicated from the scan, this is a high confidence match. |
Apache v 2.4.49c | CVE-2021-41773 Affects cpe:2.3:a:apache:http_server:2.4.49:*:*:*:*:*:*:* | Medium Confidence Match | Because the version numbers from the service and the NVD information match, except for the additional character in the version from the service, this is a medium confidence match. |
Apache v 2.4.50 | CVE-2022-22719 Affects cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* (up to and including 2.4.52) | High Confidence Match | Because the CPE information from NVD matches the version of Apache indicated from the scan, this is a high confidence match. |
Apache v 2.4.50 (Running on Red Hat Enterprise Linux 6 (RHEL6), which is not affected by this CVE) | CVE-2022-22719 Affects cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* (up to and including 2.4.52) | High Confidence Match | Because the CPE information from NVD matches the version of apache indicated from the scan, this is a high confidence match.Xpanse cannot determine if mitigating controls are in place or the underlying OS, so this pairing will still generate a high confidence match. |
In general, an Inferred CVE might impact your service, but additional investigation is required to confirm that the CVE is actually present.
Cortex Xpanse is making ongoing improvements to CVE version matching. In general, we aim to err on the side of overmatching, so you don’t miss a vulnerable service in need of patching. If you notice a version that is incorrectly matched or not matched, please contact your CSM and let them know.
Search for Instances of a Specific CVE
To search for instances of a specific CVE in your attack surface, go to the → page and filter on Externally Inferred CVEs. This will show you any services in your attack surface that match the inferred CVE. This does not confirm the presence or absence of a specific CVE.
For more detailed information about the risks of an externally inferred CVE, review the the Risk tab of an incident with that CVE. Here you will find exploit information, risk factors, and other details.