CVE-2017-15023 in binutils
Summary
by MITRE
read_formatted_entries in dwarf2.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.29, does not properly validate the format count, which allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted ELF file, related to concat_filename.
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Analysis
by VulDB Data Team • 12/30/2022
The vulnerability identified as CVE-2017-15023 resides within the Binary File Descriptor (BFD) library, a core component of GNU Binutils version 2.29. This library serves as a fundamental interface for handling various binary file formats including elf, aout, and coff, making it a critical element in software development and analysis toolchains. The flaw specifically manifests in the read_formatted_entries function located in dwarf2.c, where improper validation of format counts creates a condition that can be exploited by remote attackers to execute denial of service attacks. The vulnerability is particularly concerning because it affects a widely-used library that forms the backbone of many security tools, development environments, and binary analysis utilities.
The technical implementation of this vulnerability stems from insufficient input validation within the dwarf2.c file where the read_formatted_entries function processes formatted entries without adequately verifying the format count parameter. When a maliciously crafted ELF file is processed, the function fails to validate the format count, leading to a scenario where a NULL pointer dereference occurs during the concat_filename operation. This improper validation allows attackers to construct ELF files that, when processed by BFD-aware applications, trigger the NULL pointer dereference and subsequent application crash. The vulnerability represents a classic case of input validation failure that can be exploited to disrupt normal application operation without requiring elevated privileges or complex exploitation techniques.
The operational impact of CVE-2017-15023 extends beyond simple denial of service, as it affects the reliability and stability of systems that depend on BFD library functionality. Applications that utilize libbfd for binary analysis, debugging, or file format processing become vulnerable to crashes when encountering maliciously crafted ELF files. This vulnerability is particularly dangerous in environments where automated tools process untrusted binary data, such as malware analysis systems, package managers, or security scanning utilities. The remote attack vector means that systems can be compromised simply by processing or analyzing a crafted file, making this a significant concern for security tool developers and system administrators who must maintain robust defenses against such attacks.
Mitigation strategies for CVE-2017-15023 should focus on both immediate patching and defensive programming approaches. The primary solution involves upgrading to GNU Binutils version 2.30 or later, where the vulnerability has been addressed through proper format count validation in the read_formatted_entries function. Organizations should also implement defensive measures such as input sanitization and validation for all binary file processing operations, particularly in applications that handle untrusted input. Additionally, security monitoring should be enhanced to detect unusual patterns of application crashes or service disruptions that might indicate exploitation attempts. This vulnerability aligns with CWE-129, Input Validation, and falls under ATT&CK technique T1499.004, Network Denial of Service, highlighting the importance of robust input validation and proper error handling in security-critical software components.