CVE-2018-7570 in binutils
Summary
by MITRE
The assign_file_positions_for_non_load_sections function in elf.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.30, allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an ELF file with a RELRO segment that lacks a matching LOAD segment, as demonstrated by objcopy.
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Analysis
by VulDB Data Team • 09/04/2024
The vulnerability identified as CVE-2018-7570 resides within the Binary File Descriptor (BFD) library, specifically in the assign_file_positions_for_non_load_sections function located in elf.c. This library component is part of GNU Binutils 2.30 and serves as a foundational element for handling various binary file formats including ELF. The flaw manifests when processing ELF files that contain RELRO segments without corresponding LOAD segments, creating a scenario where the application encounters a NULL pointer dereference leading to a crash. This vulnerability affects the objcopy utility which is commonly used for copying and converting object files between different formats.
The technical implementation of this vulnerability stems from inadequate validation of ELF file structures during the processing phase. When the BFD library attempts to assign file positions for non-load sections, it assumes that all RELRO segments will have matching LOAD segments in the file. However, when this assumption proves false, the code path leads to a NULL pointer dereference rather than proper error handling. This represents a classic lack of input validation and defensive programming practices that can be classified under CWE-476 which specifically addresses NULL pointer dereference vulnerabilities. The flaw demonstrates poor error handling mechanisms within the ELF parsing routines of the BFD library.
From an operational perspective, this vulnerability creates a significant denial of service risk for systems that process untrusted ELF files through the objcopy utility or other tools relying on the BFD library. Remote attackers can craft malicious ELF files with malformed RELRO and LOAD segment relationships to trigger the crash, potentially disrupting legitimate file processing operations. The impact extends beyond simple application crashes as it can affect automated build systems, binary analysis tools, and any environment where ELF files are processed without proper validation. This vulnerability aligns with ATT&CK technique T1499.001 which covers network denial of service attacks, though in this case the attack vector involves file processing rather than network traffic.
Mitigation strategies should focus on updating to patched versions of GNU Binutils where the vulnerability has been addressed through proper input validation and error handling. Organizations should implement strict file validation processes for any ELF files processed through BFD-dependent tools, particularly in automated environments. The fix typically involves adding proper checks to ensure that RELRO segments have corresponding LOAD segments before attempting to process their file positions. Additionally, deploying sandboxed environments for processing untrusted binary files can provide an additional layer of protection against exploitation of this and similar vulnerabilities in the BFD library.