CVE-2017-2781 in MatrixSSL
Summary
by MITRE
An exploitable heap buffer overflow vulnerability exists in the X509 certificate parsing functionality of InsideSecure MatrixSSL 3.8.7b. A specially crafted x509 certificate can cause a buffer overflow on the heap resulting in remote code execution. To trigger this vulnerability, a specially crafted x509 certificate must be presented to the vulnerable client or server application when initiating secure connection.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-2781 represents a critical heap buffer overflow within the MatrixSSL 3.8.7b library's X509 certificate parsing implementation. This flaw resides in the cryptographic library's handling of certificate data structures, specifically when processing X509 certificates during TLS/SSL handshake operations. The vulnerability stems from insufficient bounds checking during the parsing of certificate fields, particularly affecting the heap memory allocation and data copying processes. Attackers can exploit this weakness by constructing malicious X509 certificates that contain oversized or malformed fields designed to exceed the allocated buffer boundaries during parsing operations.
The technical exploitation of this vulnerability occurs through a carefully crafted certificate that triggers an integer overflow or insufficient input validation during the certificate parsing sequence. When the vulnerable MatrixSSL implementation encounters such a malformed certificate, it attempts to copy certificate data into heap-allocated buffers without proper size verification, leading to memory corruption. The heap buffer overflow can be leveraged to overwrite adjacent memory locations, potentially allowing attackers to execute arbitrary code with the privileges of the affected application process. This type of vulnerability falls under CWE-121 heap-based buffer overflow, which is classified as a critical security weakness in memory management practices.
The operational impact of CVE-2017-2781 extends across various network services and applications that rely on InsideSecure MatrixSSL 3.8.7b for secure communications. Any system that accepts X509 certificates from external parties during TLS negotiation becomes a potential target, including web servers, email servers, VPN gateways, and other SSL/TLS-enabled services. The remote code execution capability means attackers can compromise entire systems without requiring local access, making this vulnerability particularly dangerous for network infrastructure components. According to ATT&CK framework, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: PowerShell) and T1078 (Valid Accounts) as attackers can potentially escalate privileges and maintain persistent access through the executed code. The exploitation typically follows the pattern of initial certificate delivery through TLS handshake initiation, making detection challenging as the malicious behavior occurs during legitimate secure communication establishment.
Mitigation strategies for CVE-2017-2781 primarily involve immediate patching of the MatrixSSL library to version 3.8.7c or later, which contains the necessary bounds checking fixes and memory management improvements. Organizations should also implement certificate validation policies that include certificate pinning and regular certificate monitoring to detect anomalous certificate structures. Network segmentation and monitoring solutions can help identify unusual certificate exchange patterns that might indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature-based detection for known malicious certificate patterns provides an extra layer of defense. The vulnerability demonstrates the critical importance of proper input validation in cryptographic libraries and aligns with the principle of defense in depth as outlined in NIST SP 800-53, where multiple security controls work together to protect against various attack vectors.