CVE-2017-3731 in MySQL Server
Summary
by MITRE
If an SSL/TLS server or client is running on a 32-bit host, and a specific cipher is being used, then a truncated packet can cause that server or client to perform an out-of-bounds read, usually resulting in a crash. For OpenSSL 1.1.0, the crash can be triggered when using CHACHA20/POLY1305; users should upgrade to 1.1.0d. For Openssl 1.0.2, the crash can be triggered when using RC4-MD5; users who have not disabled that algorithm should update to 1.0.2k.
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Analysis
by VulDB Data Team • 01/04/2023
This vulnerability represents a critical out-of-bounds read flaw in OpenSSL implementations running on 32-bit architectures, specifically affecting SSL/TLS protocol handling during packet processing. The vulnerability manifests when a server or client processes truncated packets under specific cipher suite conditions, leading to memory access violations that typically result in application crashes. The flaw exploits improper bounds checking in the SSL/TLS packet parsing logic, where the software fails to validate packet length against expected cryptographic parameters before attempting to read from memory locations beyond the allocated buffer boundaries. This issue is particularly severe on 32-bit systems due to memory addressing limitations and the way cryptographic operations are implemented in the affected OpenSSL versions.
The technical exploitation of this vulnerability requires specific conditions to be met, including the use of particular cipher suites on 32-bit platforms. For OpenSSL 1.1.0 versions, the CHACHA20/POLY1305 cipher suite triggers the vulnerability, while OpenSSL 1.0.2 versions are affected when using the RC4-MD5 cipher suite. Both scenarios demonstrate weaknesses in the packet validation mechanisms that should prevent malformed data from causing memory corruption. The out-of-bounds read occurs during the decryption and verification processes where the software attempts to access memory locations that are not properly validated against the actual packet size, creating a potential denial of service condition that can be reliably triggered by remote attackers. This type of vulnerability falls under CWE-125 Out-of-bounds Read, which is classified as a memory safety issue in the Common Weakness Enumeration framework.
The operational impact of CVE-2017-3731 extends beyond simple service disruption, as it represents a potential vector for more sophisticated attacks that could be combined with other vulnerabilities to achieve remote code execution. While the immediate effect is typically a crash leading to denial of service, the underlying memory corruption could theoretically be exploited to gain additional system access or escalate privileges, particularly in environments where the affected OpenSSL implementations are used in critical infrastructure components. The vulnerability affects a wide range of systems including web servers, email servers, and any application that relies on OpenSSL for secure communications. Organizations using 32-bit systems with affected OpenSSL versions face significant risk, as the vulnerability can be triggered through normal SSL/TLS handshakes without requiring authentication or special privileges from attackers. The specific cipher suite requirements mean that not all SSL/TLS implementations are affected, but those using the vulnerable configurations present a clear security risk that requires immediate attention.
Mitigation strategies for this vulnerability center on software updates and configuration changes that address the root cause of the memory access violation. The primary recommendation involves upgrading to the patched versions of OpenSSL, specifically 1.1.0d for the 1.1.0 series and 1.0.2k for the 1.0.2 series, which contain the necessary code modifications to properly validate packet lengths before memory access operations. Organizations should also consider disabling the vulnerable cipher suites in their configurations, particularly RC4-MD5 for 1.0.2 installations and CHACHA20/POLY1305 for 1.1.0 installations, when these specific algorithms are not required for interoperability. System administrators should implement monitoring solutions to detect potential exploitation attempts and ensure that all affected systems are updated promptly. Additionally, the vulnerability demonstrates the importance of proper input validation and bounds checking in cryptographic implementations, aligning with ATT&CK technique T1203 Exploitation for Client Execution which involves using vulnerabilities in software to gain unauthorized access. The fix addresses the underlying memory safety issue by implementing proper buffer length validation during SSL/TLS packet processing, preventing the out-of-bounds memory access that previously occurred when processing truncated packets under the specific cipher suite conditions.