CVE-2019-11640 in Recutils
Summary
by MITRE
An issue was discovered in GNU recutils 1.8. There is a heap-based buffer overflow in the function rec_fex_parse_str_simple at rec-fex.c in librec.a.
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Analysis
by VulDB Data Team • 12/05/2024
The vulnerability identified as CVE-2019-11640 represents a critical heap-based buffer overflow within GNU recutils version 1.8, specifically within the rec_fex_parse_str_simple function located in the rec-fex.c source file of the librec.a library. This flaw exists in the core parsing functionality that processes structured data records, making it a fundamental component of the software's data handling pipeline. The buffer overflow occurs when the application processes strings that exceed predetermined memory boundaries, creating opportunities for arbitrary code execution or system instability.
The technical implementation of this vulnerability stems from insufficient bounds checking during string parsing operations within the rec_fex_parse_str_simple function. When processing input data, the function fails to properly validate the length of strings before copying them into allocated heap memory buffers. This oversight allows maliciously crafted input to overwrite adjacent memory regions, potentially corrupting program execution flow or enabling attackers to inject and execute arbitrary code. The vulnerability manifests as a heap-based buffer overflow rather than a stack-based one, indicating that the problematic memory allocation occurs on the heap rather than the stack, which can make exploitation more complex but also more persistent.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides potential attackers with pathways for privilege escalation and system compromise. Since GNU recutils is commonly used for managing structured data records in various applications, an attacker who can control input to the affected library could potentially exploit this vulnerability in contexts where recutils is used as a library component. The vulnerability affects any system running GNU recutils 1.8 or earlier versions, making it particularly concerning for environments where this library is widely deployed. This issue aligns with CWE-121, heap-based buffer overflow, and represents a classic example of improper input validation leading to memory corruption vulnerabilities.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the T1059.007 technique for command and script injection, as successful exploitation could enable attackers to execute arbitrary commands on affected systems. The vulnerability also relates to T1555.003 for credentials access and T1046 for network service enumeration, as exploitation might be used to gain further access to system resources. Mitigation strategies should include immediate patching of affected systems to version 1.9 or later where this vulnerability has been resolved. Organizations should also implement input validation controls and consider runtime protections such as address space layout randomization and stack canaries to reduce the effectiveness of potential exploitation attempts. Additionally, monitoring for unusual data processing patterns or memory allocation behaviors could help detect exploitation attempts targeting this vulnerability.
The root cause of this issue demonstrates the importance of proper memory management and input validation in C-based applications, particularly those handling untrusted data. The vulnerability serves as a reminder of the critical need for thorough code review processes and the application of defensive programming techniques to prevent buffer overflow conditions. Regular security assessments and automated vulnerability scanning should be implemented to identify similar issues in other software components that may be susceptible to the same class of memory corruption vulnerabilities.