CVE Vulnerabilities

CVE-2021-33695

Improper Validation of Certificate with Host Mismatch

Published: Sep 15, 2021 | Modified: Nov 21, 2024
CVSS 3.x
9.1
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 2.x
6.4 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

Potentially, SAP Cloud Connector, version - 2.0 communication with the backend is accepted without sufficient validation of the certificate.

Weakness

The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.

Affected Software

Name Vendor Start Version End Version
Cloud_connector Sap 2.0 (including) 2.0 (including)

Extended Description

Even if a certificate is well-formed, signed, and follows the chain of trust, it may simply be a valid certificate for a different site than the site that the product is interacting with. 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. In order to ensure data integrity, the certificate must be valid and it must pertain to the site that is being accessed. Even if the product attempts to check the hostname, it is still possible to incorrectly check the hostname. For example, attackers could create a certificate with a name that begins with a trusted name followed by a NUL byte, which could cause some string-based comparisons to only examine the portion that contains the trusted name. This weakness can occur even when the product uses Certificate Pinning, if the product does not verify the hostname at the time a certificate is pinned.

Potential Mitigations

References