CVE-2018-7208 in binutils
Summary
by MITRE
In the coff_pointerize_aux function in coffgen.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.30, an index is not validated, which allows remote attackers to cause a denial of service (segmentation fault) or possibly have unspecified other impact via a crafted file, as demonstrated by objcopy of a COFF object.
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Analysis
by VulDB Data Team • 01/06/2020
The vulnerability identified as CVE-2018-7208 resides within the Binary File Descriptor (BFD) library, specifically in the coff_pointerize_aux function located in coffgen.c. This flaw exists in GNU Binutils version 2.30 and represents a classic case of insufficient input validation that can be exploited by remote attackers to disrupt system operations. The BFD library serves as a foundational component for handling various binary file formats, making this vulnerability particularly concerning as it affects the core functionality of tools like objcopy that process COFF (Common Object File Format) objects. The vulnerability manifests when an index parameter is not properly validated during the processing of COFF auxiliary entries, creating a potential pathway for malicious input to trigger unexpected behavior in the binary processing pipeline.
The technical flaw stems from the absence of proper bounds checking on an index variable within the coff_pointerize_aux function, which operates on COFF object files that are commonly used in Windows and embedded systems development. When a maliciously crafted COFF file is processed by tools such as objcopy, the function attempts to access memory locations using an unvalidated index that could exceed the allocated array boundaries. This lack of validation creates a condition where an attacker can manipulate the input file to cause the program to attempt memory access at invalid addresses, leading to segmentation faults or potentially more severe consequences depending on the specific execution context. The vulnerability is classified under CWE-129, which specifically addresses insufficient validation of length of buffers, making it a direct descendant of buffer overflow and memory corruption patterns that have long plagued binary processing utilities.
The operational impact of this vulnerability extends beyond simple denial of service, as demonstrated by the potential for unspecified other impacts that could include arbitrary code execution or information disclosure. When exploited, the vulnerability can cause objcopy and other BFD-dependent tools to crash, effectively rendering them unusable for legitimate purposes and creating a denial of service condition for systems that rely on these utilities for software development and system administration tasks. The remote nature of the attack means that an attacker could potentially compromise systems by delivering malicious COFF files through various attack vectors, including email attachments, web downloads, or file sharing platforms. This vulnerability particularly affects systems that process untrusted binary content, such as build servers, automated testing environments, or any system where objcopy or similar BFD tools are executed on user-provided files without proper sanitization.
Mitigation strategies for CVE-2018-7208 should focus on immediate patching of affected GNU Binutils installations to version 2.31 or later, where the index validation has been properly implemented. Organizations should also implement strict input validation procedures for any binary files processed through BFD-dependent tools, particularly in automated environments where untrusted content might be encountered. Network administrators should consider implementing file type restrictions and content scanning for COFF files, especially in environments where objcopy or similar tools are executed with elevated privileges. The ATT&CK framework categorizes this vulnerability under T1059.007 for execution through command and scripting interpreter, and T1499.004 for network denial of service, making it relevant for both execution and denial of service attack scenarios. System administrators should also monitor for abnormal process termination or segmentation fault occurrences in systems where BFD tools are actively used, as these could indicate exploitation attempts. Additionally, implementing proper access controls and privilege separation for binary processing utilities can limit the potential impact of successful exploitation, as the vulnerability requires execution of the affected BFD tools to be effective.