CVE-2017-14940 in binutils
Summary
by MITRE
scan_unit_for_symbols in dwarf2.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.29, allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted ELF file.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-14940 resides within the Binary File Descriptor (BFD) library, specifically in the scan_unit_for_symbols function located in dwarf2.c. This flaw affects GNU Binutils version 2.29 and represents a critical denial of service vulnerability that can be exploited remotely through crafted ELF files. The BFD library serves as a fundamental component for handling various binary file formats including ELF, COFF, and Mach-O, making this vulnerability particularly concerning as it impacts numerous software tools that depend on this library for binary analysis and processing. The vulnerability manifests when the application attempts to process malformed ELF files that contain specially crafted dwarf debugging information, leading to a null pointer dereference that causes the application to crash and terminate unexpectedly.
The technical root cause of this vulnerability stems from inadequate input validation within the dwarf2.c file where the scan_unit_for_symbols function fails to properly validate pointer references when processing dwarf debugging sections in ELF files. When a maliciously crafted ELF file is processed, the function attempts to access a null pointer that has not been properly initialized or validated, resulting in an immediate application crash. This type of vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions. The flaw occurs during the parsing of dwarf debugging information where the application expects certain data structures to be properly initialized but encounters malformed data that leads to the null pointer dereference. The vulnerability is particularly dangerous because it can be triggered through normal file processing operations, meaning that any application utilizing the BFD library to process ELF files could be affected, including debuggers, disassemblers, and binary analysis tools.
The operational impact of CVE-2017-14940 extends beyond simple application crashes to potentially disrupt critical system operations and security analysis workflows. Attackers can exploit this vulnerability to perform denial of service attacks against systems that process binary files, including security tools, build systems, and automated analysis platforms. The vulnerability can be leveraged in various attack scenarios including web-based file upload systems, automated binary analysis pipelines, and security scanning tools that process user-provided files. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1499.004 which involves network denial of service attacks and T1059.007 which covers command and scripting interpreter execution. The vulnerability affects the availability of services that depend on BFD library functionality, potentially allowing attackers to disrupt legitimate operations and create service interruptions in environments where automated binary processing is critical.
Mitigation strategies for CVE-2017-14940 primarily focus on updating to patched versions of GNU Binutils where the vulnerability has been resolved through proper input validation and null pointer checks. System administrators should prioritize upgrading to GNU Binutils 2.30 or later versions which contain the necessary fixes for this vulnerability. Additionally, implementing input validation controls at the application level can provide defense in depth, ensuring that potentially malicious ELF files are rejected before they reach the BFD library processing functions. Organizations should also consider implementing sandboxing mechanisms when processing unknown binary files to isolate potential exploitation attempts. The fix implemented in the patched versions typically involves adding proper null pointer checks and validation routines before pointer dereferences, ensuring that the scan_unit_for_symbols function properly handles malformed dwarf debugging sections without causing application crashes. Security monitoring should be enhanced to detect unusual application termination patterns that may indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify other potential weaknesses in binary processing pipelines that may be susceptible to similar classes of vulnerabilities.