CVE-2017-12967 in binutils
Summary
by MITRE
The getsym function in tekhex.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.29, allows remote attackers to cause a denial of service (stack-based buffer over-read and application crash) via a malformed tekhex binary.
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Analysis
by VulDB Data Team • 11/09/2019
The vulnerability identified as CVE-2017-12967 represents a critical stack-based buffer over-read flaw within the Binary File Descriptor library's tekhex.c component, specifically affecting GNU Binutils version 2.29. This issue stems from inadequate input validation in the getsym function, which processes tekhex binary format files. The flaw occurs when the BFD library attempts to parse malformed binary data, causing the application to read beyond the bounds of allocated memory buffers. Such buffer over-read conditions are classified under CWE-125 as out-of-bounds read vulnerabilities, which can lead to unpredictable behavior including application crashes, data corruption, or in some cases, potential code execution. The vulnerability is particularly concerning because it can be triggered remotely through the processing of maliciously crafted binary files, making it a significant threat to systems that handle untrusted binary data.
The technical implementation of this vulnerability involves the getsym function in tekhex.c failing to properly validate the length of data being read from tekhex format binary files. When processing malformed input, the function attempts to access memory locations beyond the allocated buffer boundaries, resulting in a stack-based buffer over-read condition. This type of vulnerability falls under the ATT&CK framework's technique T1059.007 for command and scripting interpreter, as it can be exploited through the manipulation of binary file processing routines. The flaw demonstrates a classic buffer management error where the application does not properly check input boundaries before performing memory operations. The stack-based nature of the over-read means that the vulnerability can potentially corrupt adjacent stack memory, leading to application instability or complete crash scenarios.
From an operational perspective, this vulnerability poses significant risks to systems that rely on GNU Binutils for binary file processing, including software development environments, security analysis tools, and automated build systems. The denial of service impact can disrupt critical workflows where binary file processing is essential, potentially affecting software compilation, debugging, or analysis operations. Attackers could exploit this vulnerability by crafting malicious tekhex binary files that, when processed by affected applications, would trigger the buffer over-read condition. The remote exploitation capability makes this vulnerability particularly dangerous in environments where untrusted binary data might be processed automatically, such as in software distribution systems or automated security analysis platforms. This vulnerability impacts the availability and reliability of systems that depend on the BFD library for binary format handling.
Mitigation strategies for CVE-2017-12967 should prioritize immediate patching of affected GNU Binutils installations to version 2.30 or later, which contains the necessary fixes for the buffer over-read condition. Organizations should implement strict input validation controls for all binary file processing operations, particularly when handling untrusted data sources. Security teams should consider deploying sandboxing mechanisms when processing unknown binary formats to isolate potential exploitation attempts. Additionally, network segmentation and access controls should be enforced to limit exposure to systems that process binary data from external sources. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing robust input validation practices to prevent similar buffer over-read conditions in other components of the software supply chain. System administrators should monitor for any signs of exploitation attempts and maintain comprehensive logging of binary file processing activities to detect potential abuse of this vulnerability.