CVE-2018-6872 in binutils
Summary
by MITRE
The elf_parse_notes 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 (out-of-bounds read and segmentation violation) via a note with a large alignment.
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Analysis
by VulDB Data Team • 09/04/2024
The vulnerability identified as CVE-2018-6872 resides within the Binary File Descriptor (BFD) library, specifically in the elf_parse_notes function located in elf.c. This library component is part of GNU Binutils 2.30 and serves as a fundamental tool for handling binary file formats across various operating systems. The flaw manifests when processing ELF (Executable and Linkable Format) files that contain malformed note sections with excessive alignment values. Such notes can originate from various sources including maliciously crafted binaries, compromised software distributions, or improperly generated executables, creating potential attack vectors for remote adversaries seeking to disrupt system operations.
The technical implementation of this vulnerability stems from inadequate input validation within the elf_parse_notes function which fails to properly sanitize the alignment field of note sections. When the BFD library encounters a note with an abnormally large alignment value, the parsing routine attempts to access memory locations beyond the bounds of allocated buffers, resulting in out-of-bounds read operations. This memory corruption leads to segmentation violations and subsequent program termination, effectively causing a denial of service condition. The vulnerability operates at the level of binary file parsing and can be triggered during normal file processing activities, making it particularly dangerous as it can be exploited through routine system operations without requiring special privileges or user interaction.
The operational impact of CVE-2018-6872 extends beyond simple denial of service scenarios, as it can compromise the stability and reliability of systems that depend on BFD library functionality. Applications and services that utilize libbfd for binary analysis, file format identification, or software debugging may become vulnerable to crashes when processing maliciously crafted ELF files. This includes security tools, system monitoring applications, automated build systems, and any software that performs routine binary file analysis. The vulnerability can be particularly problematic in environments where automated processing of user-supplied binaries occurs, such as software repositories, malware analysis platforms, or continuous integration systems, where a single malicious file could cause widespread disruption.
Mitigation strategies for CVE-2018-6872 should focus on both immediate remediation and long-term architectural improvements. The most direct solution involves upgrading to GNU Binutils version 2.31 or later, where the vulnerability has been addressed through enhanced input validation and proper bounds checking. Organizations should also implement defensive measures such as input sanitization for binary file processing, implementing strict file format validation, and deploying automated scanning tools to detect potentially malicious ELF files before they are processed. From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and can be mapped to ATT&CK technique T1059.007 for execution through command-line interfaces that may invoke vulnerable BFD functionality. Additionally, implementing network segmentation, access controls, and regular security assessments can help reduce the attack surface and prevent exploitation of this vulnerability across enterprise environments.