CVE-2020-15719
Description
From CVE.org
libldap in certain third-party OpenLDAP packages has a certificate-validation flaw when the third-party package is asserting RFC6125 support. It considers CN even when there is a non-matching subjectAltName (SAN). This is fixed in, for example, openldap-2.4.46-10.el8 in Red Hat Enterprise Linux.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.2 | 4.2 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Red Hat CVSS v3 Score Explanation
Red Hat's explanations regarding the CVSS scoring :
AC:H : The opportunity to get a certificate matching the requirements is considered minimal, increasing the complexity of a attack. The attacker would also need to actively intercept the connection.
UI:R : A client would need to connect to the server for an attacker to intercept this connection. This is usually created from a user interaction
A:N : An attacker with the ability to actively interact with a connection is able to break it regardless of the vulnerability. Availability is not taken into account by this attack.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
The data read from the system vouched for by the certificate may not be from the expected system.
Authentication,Other
Technical Impact: Other
Trust afforded to the system in question - based on the malicious certificate - may allow for spoofing or redirection attacks.
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Other
If the certificate's host-specific data is not properly checked - such as the Common Name (CN) in the Subject or the Subject Alternative Name (SAN) extension of an X.509 certificate - it may be possible for a redirection or spoofing attack to allow a malicious host with a valid certificate to provide data, impersonating a trusted host.
Acknowledgements
Red Hat would like to thank Christian Heimes and Jakub Hrozek for reporting this issue.
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