2021-3450 | Oracle MySQL Connectors OpenSSL certificate validation

By Max On Jul 24, 2021

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7.1	$0-$5k	1.55

A vulnerability was found in Oracle MySQL Connectors up to 8.0.23 (Database Software). It has been classified as critical. Affected is some unknown functionality of the component OpenSSL. The manipulation with an unknown input leads to a weak authentication vulnerability. CWE is classifying the issue as CWE-295. This is going to have an impact on confidentiality, and integrity. CVE summarizes:

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a “purpose” has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named “purpose” values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j).

The weakness was published 07/20/2021 as Oracle Critical Patch Update Advisory – July 2021. The advisory is shared for download at oracle.com. This vulnerability is traded as CVE-2021-3450 since 03/19/2021. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn’t require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/24/2021). The MITRE ATT&CK project declares the attack technique as T1587.003.

Upgrading eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

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