CVE-2019-16396 in GnuCOBOL
Summary
by MITRE
GnuCOBOL 2.2 has a use-after-free in the end_scope_of_program_name() function in cobc/parser.y via crafted COBOL source code.
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Analysis
by VulDB Data Team • 12/26/2023
The vulnerability identified as CVE-2019-16396 represents a critical use-after-free condition within the GnuCOBOL compiler version 2.2, specifically within the end_scope_of_program_name() function located in cobc/parser.y. This flaw manifests when processing crafted COBOL source code that exploits memory management issues during the compilation process. The vulnerability stems from improper handling of memory allocation and deallocation sequences, where a program reference is accessed after the memory it points to has been freed, creating potential opportunities for arbitrary code execution or system instability.
This use-after-free vulnerability operates at the compiler level rather than at runtime, making it particularly concerning for development environments where code compilation occurs. The flaw exists in the parser component of GnuCOBOL, which is responsible for analyzing and processing COBOL source code syntax. When maliciously constructed COBOL programs are compiled, the end_scope_of_program_name() function fails to properly manage memory references, leading to situations where freed memory locations are accessed, potentially causing memory corruption. The vulnerability is classified under CWE-416 as Use After Free, which is a well-documented weakness in software security that allows attackers to manipulate memory access patterns and potentially execute malicious code.
The operational impact of this vulnerability extends beyond simple compilation failures, as it can be exploited by attackers who craft specific COBOL source code patterns designed to trigger the memory corruption. When a vulnerable compiler processes such malicious code, the use-after-free condition can lead to unpredictable behavior including crashes, data corruption, or in more severe cases, arbitrary code execution on the system where the compiler is running. This represents a significant risk for organizations that compile untrusted COBOL code or operate in environments where code integrity cannot be guaranteed. The vulnerability affects any system running GnuCOBOL 2.2 and is particularly dangerous in automated build environments or continuous integration systems where code compilation occurs frequently.
Security professionals should note that this vulnerability aligns with ATT&CK technique T1059.006 for Compiler and T1059.008 for Interpreter, as it exploits the compilation process itself to introduce malicious behavior. The attack surface is primarily limited to development and build environments where GnuCOBOL is installed, but the implications are severe given that attackers could potentially compromise systems through compromised compilation processes. Mitigation strategies should focus on immediate patching to GnuCOBOL version 2.2 or later, where the memory management issues have been addressed. Organizations should also implement strict code review processes for any COBOL source code that will be compiled, particularly in environments where code authenticity cannot be verified. Additionally, sandboxing compilation processes and implementing automated vulnerability scanning for source code before compilation can help reduce the risk of exploitation. The vulnerability highlights the importance of memory safety in compiler development and underscores the need for proper input validation and memory management practices in all software components that handle user-provided data.