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A. Nature of the Vulnerability
- X.509 Email Address 4-byte Buffer Overflow (CVE-2022-3602)
A buffer overrun can be triggered in X.509 certificate verification, specifically in name constraint checking. Note that this occurs after certificate chain signature verification and requires either a CA to have signed the malicious certificate or for the application to continue certificate verification despite failure to construct a path to a trusted issuer. An attacker can craft a malicious email address to overflow four attacker-controlled bytes on the stack. This buffer overflow could result in a crash (causing a denial of service) or potentially remote code execution.
- X.509 Email Address Variable Length Buffer Overflow (CVE-2022-3786)
A buffer overrun can be triggered in X.509 certificate verification, specifically in name constraint checking. Note that this occurs after certificate chain signature verification and requires either a CA to have signed a malicious certificate or for an application to continue certificate verification despite failure to construct a path to a trusted issuer. An attacker can craft a malicious email address in a certificate to overflow an arbitrary number of bytes containing the `.’ character (decimal 46) on the stack. This buffer overflow could result in a crash (causing a denial of service).
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B. Actions to be Taken
- CERT-PH encourages all OpenSSL users/administrators using versions 3.0.0 to 3.0.6 to review and apply the updates to mitigate future threats.
- If users cannot update to the latest version and run a TLS Server. Users may consider disabling TLS client authentication if it is being used until fixes are applied.
- Regularly check and apply the latest patch of software, especially to public-facing applications.
- Proactively monitor and secure identified systems and devices for any suspicious/malicious activities.
- For additional information, kindly refer to the official advisory:
- <https://www.openssl.org/blog/blog/2022/11/01/email-address-overflows/>
- <https://www.openssl.org/news/secadv/20221101.txt>