CVE-2018-16430 in Libextractor
Summary
by MITRE
GNU Libextractor through 1.7 has an out-of-bounds read vulnerability in EXTRACTOR_zip_extract_method() in zip_extractor.c.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-16430 represents a critical out-of-bounds read flaw within GNU Libextractor version 1.7 and earlier, specifically affecting the EXTRACTOR_zip_extract_method() function located in the zip_extractor.c source file. This issue arises when the library processes zip archives, creating a scenario where memory access occurs beyond the allocated buffer boundaries. The vulnerability stems from inadequate input validation and boundary checking mechanisms within the zip extraction logic, allowing maliciously crafted zip files to trigger memory corruption conditions that could lead to arbitrary code execution or system instability.
The technical implementation of this vulnerability demonstrates a classic buffer overread condition that aligns with CWE-125, which describes out-of-bounds read vulnerabilities in software systems. When the EXTRACTOR_zip_extract_method() function processes zip archive entries, it fails to properly validate the size and structure of compressed data before attempting to read from memory regions. This flaw particularly manifests during the extraction of zip file metadata, where the library assumes certain data structures maintain expected sizes and formats without proper verification. The absence of proper bounds checking allows attackers to craft zip files containing malformed or oversized headers that cause the extraction routine to access memory locations outside the intended buffer, potentially exposing sensitive information or enabling exploitation techniques.
From an operational perspective, this vulnerability presents significant risks to systems that utilize GNU Libextractor for processing untrusted zip archives, including web applications, file processing services, and content management systems. The impact extends beyond simple denial of service scenarios, as the out-of-bounds read could potentially be leveraged to disclose memory contents, corrupt program execution flow, or serve as a precursor to more sophisticated exploitation techniques. The vulnerability's exploitation requires an attacker to have the ability to influence the zip files processed by the vulnerable library, making it particularly concerning in environments where users can upload or download archive files. Systems running vulnerable versions of GNU Libextractor are susceptible to remote code execution if the library is used in contexts where untrusted input is processed without proper sanitization.
The mitigation strategy for CVE-2018-16430 requires immediate patching of GNU Libextractor to version 1.8 or later, which contains the necessary fixes for the boundary checking issues in zip extraction routines. Organizations should implement comprehensive input validation measures for all zip file processing activities, including thorough file format verification before any extraction operations commence. Network administrators should consider implementing file type restrictions and content scanning mechanisms to prevent potentially malicious zip archives from reaching systems that utilize vulnerable library versions. Additionally, system hardening measures such as address space layout randomization and stack canaries should be enabled to reduce the effectiveness of potential exploitation attempts. This vulnerability also highlights the importance of regular security updates and vulnerability assessments in software supply chains, particularly for widely-used libraries that form foundational components of larger applications and systems. The remediation process should include thorough testing of patched versions to ensure that the fix does not introduce regressions in legitimate zip file processing functionality while maintaining the security improvements necessary to address the identified vulnerability.