Two new high severity vulnerabilities have been identified in the OpenSSL Software Foundation cryptographic library version 3.0.0. This open-source library is used to encrypt HTTPS connections and other communication channels, so has been relied upon by many as a security measure. These new vulnerabilities could cause denial of service or possible remote code execution to take place, compromising the security of the service being provided. OpenSSL released a security advisory this week detailing these two vulnerabilities and stating that there is currently no evidence of a working exploit for either flaw at the time of publishing.  Both flaws are exploited by specially crafting a malicious certificate with malformed email addresses. 

The first vulnerability, tracked as CVE-2022-3602, was originally described as a critical severity flaw, however this has since been downgraded to ‘high’ severity. The flaw occurs within the X.509 certificate verification functionality and requires a CA to have signed the malicious certificate. A malicious certificate can be created which contains a specially crafted email address causing the content to overflow into the buffer. The presence of code in the buffer can allow for remote code execution, or cause denial of service by causing the application to crash.  

The second vulnerability, tracked as CVE-2022-3786, is a high severity vulnerability that occurs within the same X.509 certificate verification region. This vulnerability similarly can cause a buffer overrun though manipulation of the name constraint checking and malicious certificate verification. For an attacker to exploit this flaw, they need to include a number of bytes containing the `.’ character (decimal 46) when they craft their malicious email address which is encoded in the certificate. This results in a buffer overflow, which causes the application to crash, causing denial of service. 

Users should update the version of OpenSSL they use to version 3.0.7 if they are currently using any versions prior to this release. This version includes patches for both of these vulnerabilities and can be downloaded from the OpenSSL source website. Any users of OpenSSL versions 1.1.1 and 1.0.2 are not affected by either of these flaws.