CVE-2017-8393 in binutils
Summary
by MITRE
The Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.28, is vulnerable to a global buffer over-read error because of an assumption made by code that runs for objcopy and strip, that SHT_REL/SHR_RELA sections are always named starting with a .rel/.rela prefix. This vulnerability causes programs that conduct an analysis of binary programs using the libbfd library, such as objcopy and strip, to crash.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/04/2024
The vulnerability identified as CVE-2017-8393 represents a critical buffer over-read flaw within the Binary File Descriptor library, commonly known as BFD or libbfd, which forms a core component of the GNU Binutils suite. This library serves as a fundamental interface for handling various binary file formats, making it an essential tool for developers, system administrators, and security professionals who work with executable and object files. The flaw specifically manifests in version 2.28 of GNU Binutils, where the BFD library's implementation contains a logical error that stems from an incorrect assumption about section naming conventions in ELF binary files. This vulnerability affects the objcopy and strip utilities, which are widely used tools for copying and modifying binary files, making the impact particularly widespread across various computing environments where these utilities are employed for system maintenance, software development, and security analysis operations.
The technical root cause of this vulnerability lies in the code's assumption that sections of type SHT_REL and SHT_RELA (which represent relocation sections in ELF binary formats) will always be named with a specific prefix consisting of a period followed by either "rel" or "rela". This assumption breaks down when encountering binary files where relocation sections have different naming conventions or when the section names do not conform to the expected pattern. When the BFD library processes such binaries, it attempts to read beyond the bounds of allocated memory buffers, leading to a global buffer over-read condition that can result in unpredictable program behavior. This type of vulnerability falls under the CWE-121 category of buffer over-read conditions, which are particularly dangerous because they can lead to system crashes, data corruption, or potentially more severe security implications depending on how the affected applications are used in practice. The flaw demonstrates a classic example of insufficient input validation and buffer management within a widely-used system library, where the assumption about file format conventions proves to be incorrect in real-world scenarios.
The operational impact of CVE-2017-8393 extends far beyond simple program crashes, as it affects critical system maintenance and development tools that millions of users rely upon daily. When objcopy and strip utilities encounter malformed binary files or files with non-standard section naming, they can experience segmentation faults or other forms of memory corruption that halt operations entirely. This vulnerability particularly affects automated build systems, package managers, and security analysis tools that depend on these utilities for processing binary content, potentially causing cascading failures in software deployment pipelines and system administration tasks. The vulnerability's presence in GNU Binutils 2.28 means that any system using this version of the toolchain could be susceptible to denial-of-service attacks or other disruptions, especially when processing untrusted binary content from external sources. From an attack perspective, this vulnerability aligns with the ATT&CK technique of privilege escalation through software supply chain compromises, where an attacker could potentially craft malicious binaries designed to trigger this specific buffer over-read condition when processed by affected tools.
The mitigation strategy for CVE-2017-8393 involves immediate upgrading to GNU Binutils version 2.29 or later, where the BFD library has been patched to properly validate section names before attempting to process them. System administrators should prioritize updating their environments, particularly in production systems where these utilities are heavily used for software deployment and maintenance. Additionally, organizations should implement proper input validation for binary files processed through these tools, especially when dealing with untrusted content, and consider implementing sandboxing techniques to isolate potentially malicious binaries during processing. The fix implemented in the patched versions addresses the core assumption error by adding proper bounds checking and validation before buffer operations, ensuring that the BFD library can gracefully handle various section naming conventions without crashing. Security teams should also monitor their systems for any signs of exploitation attempts targeting this vulnerability, particularly in environments where automated processing of binary files occurs, as this vulnerability could potentially be leveraged in more sophisticated attacks targeting system stability and availability.