CVE-2017-6965 in binutils
Summary
by MITRE
readelf in GNU Binutils 2.28 writes to illegal addresses while processing corrupt input files containing symbol-difference relocations, leading to a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 03/17/2017
The vulnerability identified as CVE-2017-6965 represents a critical heap-based buffer overflow in GNU Binutils 2.28's readelf utility when processing malformed input files containing symbol-difference relocations. This flaw exists within the binary analysis toolchain that is widely used for examining object files and executable binaries across various operating systems and architectures. The vulnerability stems from insufficient input validation and improper memory management during the processing of relocation entries in ELF (Executable and Linkable Format) files, which are standard binary formats used in unix-like systems and linux environments.
The technical implementation of this vulnerability occurs when readelf encounters a corrupt input file with symbol-difference relocations that contain malformed or unexpected data structures. During processing, the utility attempts to write data to memory locations that are either outside the allocated buffer boundaries or to addresses that are not properly mapped in memory. This behavior creates a heap-based buffer overflow condition where adjacent memory regions can be overwritten, potentially leading to arbitrary code execution or application crashes. The flaw specifically manifests in the relocation processing logic where the utility fails to properly validate the bounds of symbol-difference relocation entries before attempting to access or modify associated memory regions.
From an operational standpoint, this vulnerability presents significant risks to systems that rely on GNU Binutils for binary analysis, particularly in automated build environments, security scanning tools, and software development workflows. Attackers could exploit this vulnerability by crafting malicious ELF files with carefully constructed symbol-difference relocations that trigger the buffer overflow when processed by readelf. The impact extends beyond simple application crashes to potentially enable privilege escalation or remote code execution depending on the execution context. This vulnerability affects not only direct users of readelf but also systems that depend on binutils for various security and analysis functions, making it a critical concern for system administrators and security professionals.
The vulnerability aligns with CWE-121 heap-based buffer overflow and relates to ATT&CK technique T1059.007 for execution through command-line interface, as well as T1548.001 for privilege escalation. Mitigation strategies include immediate patching of GNU Binutils to version 2.29 or later where the vulnerability has been addressed through improved input validation and memory boundary checking. Organizations should also implement input sanitization measures when processing untrusted binary files, deploy runtime protection mechanisms such as address space layout randomization and stack canaries, and consider using alternative binary analysis tools that have been verified to handle malformed inputs more robustly. Additionally, security monitoring should be enhanced to detect unusual patterns in binary analysis tool usage that might indicate exploitation attempts.