Analytics Story: OpenSSL CVE-2022-3602

Description

OpenSSL recently disclosed two vulnerabilities CVE-2022-3602 and CVE-2022-3786. CVE-2022-3602 is a X.509 Email Address 4-byte Buffer Overflow where puny code is utilized. This only affects OpenSSL 3.0.0 - 3.0.6.

Why it matters

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). In a TLS client, this can be triggered by connecting to a malicious server. In a TLS server, this can be triggered if the server requests client authentication and a malicious client connects. Users of OpenSSL 3.0.0 - 3.0.6 are encouraged to upgrade to 3.0.7 as soon as possible. If you obtain your copy of OpenSSL from your Operating System vendor or other third party then you should seek to obtain an updated version from them as soon as possible. SSL Certificates with Punycode will identify SSL certificates with Punycode. Note that it does not mean it will capture malicious payloads. If using Zeek, modify the Zeek x509 certificate with punycode to match your environment. We found during this exercise that the FULL x509 with SAN must be captured and stored, decoded, in order to query against it.

Detections

Data Sources

References

• https://www.openssl.org/blog/blog/2022/11/01/email-address-overflows/
• https://github.com/advisories/GHSA-h8jm-2x53-xhp5
• https://community.emergingthreats.net/t/out-of-band-ruleset-update-summary-2022-11-01/117
• https://github.com/corelight/CVE-2022-3602/tree/master/scripts

Source: GitHub | Version: 1