CVE-2017-12458 in binutils
Summary
by MITRE
The nlm_swap_auxiliary_headers_in function in bfd/nlmcode.h in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.29 and earlier, allows remote attackers to cause an out of bounds heap read via a crafted nlm file.
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Analysis
by VulDB Data Team • 01/07/2021
The vulnerability identified as CVE-2017-12458 resides within the Binary File Descriptor (BFD) library, a core component of GNU Binutils that serves as a universal file format abstraction layer for handling various binary file types. This flaw specifically affects the nlm_swap_auxiliary_headers_in function located in bfd/nlmcode.h, which is responsible for processing NLM (NetWare Linker Module) files. The issue manifests when the BFD library processes maliciously crafted NLM files, creating a scenario where remote attackers can exploit heap memory access patterns to perform out-of-bounds reads.
The technical implementation of this vulnerability stems from inadequate input validation and memory boundary checking within the NLM file parsing logic. When the nlm_swap_auxiliary_headers_in function processes auxiliary headers in NLM files, it fails to properly validate the size and structure of these headers before attempting to read from heap memory locations. This allows attackers to craft NLM files with malformed auxiliary header data that causes the function to access memory beyond the allocated buffer boundaries, resulting in information disclosure through heap content exposure.
From an operational perspective, this vulnerability represents a significant security risk for systems that process untrusted binary files, particularly those handling network-based file transfers or file processing workflows. The out-of-bounds heap read can potentially expose sensitive information stored in adjacent memory locations, including cryptographic keys, session tokens, or other confidential data that may reside in the heap memory space. The remote exploitability aspect means that attackers can leverage this vulnerability without requiring local system access, making it particularly dangerous in networked environments where file processing occurs automatically.
The impact of this vulnerability aligns with CWE-125 Out-of-bounds Read, which classifies this issue as a memory safety error that can lead to information disclosure and potential escalation to more severe attacks. According to ATT&CK framework, this vulnerability maps to T1059 Command and Scripting Interpreter and T1552 Steal Application Access Token, as it can be used to extract sensitive information from memory that could later be exploited for privilege escalation or credential theft. The vulnerability affects all systems running GNU Binutils versions 2.29 and earlier, including various Linux distributions, embedded systems, and network appliances that rely on BFD for file format processing.
Mitigation strategies for CVE-2017-12458 primarily involve upgrading to GNU Binutils version 2.30 or later, which contains the patched implementation of the nlm_swap_auxiliary_headers_in function with proper bounds checking. Organizations should also implement network-based file validation and sandboxing mechanisms for processing untrusted binary files, particularly those that may contain NLM format data. Additional defensive measures include monitoring for unusual memory access patterns, implementing network segmentation for file processing systems, and conducting regular vulnerability assessments to identify other potential heap-based memory safety issues in similar library components. The vulnerability demonstrates the critical importance of proper input validation and memory boundary checking in security-critical libraries, as even seemingly benign file processing functions can become attack vectors when insufficiently protected against malformed input data.