CVE-2022-3602: OpenSSL Buffer Overflow Vulnerability

CVE-2022-3602 Overview

CVE-2022-3602 is a buffer overrun vulnerability in OpenSSL's X.509 certificate verification process, specifically occurring during name constraint checking. This vulnerability allows an attacker to craft a malicious email address that overflows four attacker-controlled bytes on the stack during certificate verification. The buffer overflow could result in a crash causing denial of service, or potentially enable remote code execution under certain conditions.

The vulnerability occurs after certificate chain signature verification and requires either a Certificate Authority (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. In TLS client scenarios, exploitation can be triggered by connecting to a malicious server. In TLS server scenarios, it can be triggered when the server requests client authentication and a malicious client connects.

Critical Impact

This vulnerability was initially pre-announced as CRITICAL but was subsequently downgraded to HIGH severity after further analysis revealed mitigating factors including platform stack overflow protections and varying stack layouts across different platform/compiler combinations.

Affected Products

• OpenSSL versions 3.0.0 through 3.0.6
• Fedora Project Fedora (versions 26, 27, 36, 37)
• NetApp Clustered Data ONTAP
• Node.js (versions 18.12.0 LTS and 19.0.0)

Discovery Timeline

• November 1, 2022 - CVE-2022-3602 published to NVD
• November 1, 2022 - OpenSSL releases security patch in version 3.0.7
• November 4, 2025 - Last updated in NVD database

Technical Details for CVE-2022-3602

Vulnerability Analysis

This vulnerability represents a classic stack-based buffer overflow condition in a critical cryptographic library. The flaw resides in the X.509 certificate name constraint checking functionality, which is invoked during the certificate verification process. When processing specially crafted email address fields within X.509 certificates, the verification routine fails to properly validate input length before copying data to a fixed-size stack buffer.

The overflow is constrained to four bytes, which limits but does not eliminate the potential for exploitation. The attacker maintains control over the content of these four bytes, creating opportunities for various attack scenarios depending on the target platform's memory layout and security mechanisms. Many modern operating systems implement stack canaries, ASLR (Address Space Layout Randomization), and other protections that significantly complicate successful exploitation for code execution.

Root Cause

The root cause is improper bounds checking during the processing of email address name constraints in X.509 certificates. The vulnerable code path assumes a maximum length for the email address field but fails to enforce this limit before writing to a stack-allocated buffer. This creates an out-of-bounds write condition (CWE-787) where attacker-controlled data can overflow into adjacent stack memory.

Attack Vector

The attack vector is network-based and does not require authentication or user interaction. An attacker can exploit this vulnerability through the following scenarios:

TLS Client Attack: An attacker operates a malicious TLS server presenting a certificate containing a specially crafted email address in the name constraints extension. When a vulnerable client connects and performs certificate verification, the buffer overrun is triggered.

TLS Server Attack: When a TLS server is configured to request client certificates for authentication, an attacker can present a malicious client certificate containing the crafted payload. During verification of the client certificate, the overflow occurs.

The exploitation requires either a legitimate CA to sign the malicious certificate (unlikely in practice) or relies on applications that continue processing despite certificate chain validation failures.

Detection Methods for CVE-2022-3602

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications using OpenSSL 3.0.x during TLS handshakes
• Core dumps indicating stack corruption in OpenSSL certificate verification functions
• Anomalous TLS connections with certificates containing unusually long or malformed email address fields
• Application log entries showing certificate verification failures followed by process termination

Detection Strategies

• Deploy network intrusion detection rules to identify TLS certificates with abnormally long email address name constraints
• Monitor for process crashes in OpenSSL-dependent applications with stack corruption signatures
• Implement runtime application self-protection (RASP) to detect buffer overflow attempts in cryptographic operations
• Use vulnerability scanners to identify systems running affected OpenSSL 3.0.x versions

Monitoring Recommendations

• Enable verbose logging for TLS certificate verification events across all OpenSSL-dependent services
• Configure crash monitoring and alerting for applications performing certificate verification
• Monitor network traffic for unusual certificate patterns, particularly in name constraint extensions
• Audit certificate authority trust stores for any unauthorized or suspicious certificates

How to Mitigate CVE-2022-3602

Immediate Actions Required

• Upgrade OpenSSL to version 3.0.7 or later immediately on all affected systems
• Identify all applications and services using OpenSSL 3.0.x in your environment through software inventory
• Prioritize patching for internet-facing TLS services and applications that perform client certificate authentication
• Review certificate verification configurations and ensure applications properly reject invalid certificate chains

Patch Information

OpenSSL has released version 3.0.7 which addresses this vulnerability. The fix is available from the OpenSSL Security Advisory. Organizations should update their OpenSSL installations to version 3.0.7 or later. For systems where direct OpenSSL updates are not possible, check with your operating system vendor for backported patches.

Additional vendor advisories are available from:

• Fedora Project Security Updates
• NetApp Security Advisory
• Cisco Security Advisory
• Gentoo Linux Security Advisory GLSA 202211-01

Workarounds

• If immediate patching is not possible, consider disabling TLS client certificate authentication where feasible
• Implement network segmentation to limit exposure of vulnerable services to untrusted networks
• Deploy web application firewalls or TLS inspection proxies capable of filtering malformed certificates
• Enable compiler-level stack protection mechanisms (stack canaries, ASLR) on platforms where they may not be default

# Verify OpenSSL version and upgrade on Debian/Ubuntu systems
openssl version
sudo apt update && sudo apt install openssl

# Verify OpenSSL version and upgrade on RHEL/CentOS systems
openssl version
sudo yum update openssl

# Check for applications linked against vulnerable OpenSSL
ldd /path/to/application | grep libssl