CVE-2019-9076 in binutils
Summary
by MITRE
An issue was discovered in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.32. It is an attempted excessive memory allocation in elf_read_notes in elf.c.
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Analysis
by VulDB Data Team • 07/19/2023
The vulnerability identified as CVE-2019-9076 represents a critical memory allocation flaw within the Binary File Descriptor library, commonly known as BFD or libbfd, which is a core component of the GNU Binutils suite. This library serves as a fundamental tool for handling various binary file formats, including object files, executables, and archives, making it an essential element in software development, debugging, and system administration workflows across numerous operating systems and architectures.
The technical flaw manifests specifically within the elf_read_notes function located in the elf.c source file of the BFD library. This function is responsible for parsing note sections within ELF (Executable and Linkable Format) files, which contain metadata about the binary and its associated program headers. The vulnerability occurs when the library processes malformed or maliciously crafted ELF files that contain excessive or malformed note entries, leading to an attempted memory allocation that exceeds reasonable bounds. This excessive allocation behavior stems from insufficient input validation and bounds checking within the note parsing logic, allowing an attacker to trigger a memory allocation that could potentially exhaust system resources or cause the application to crash.
The operational impact of this vulnerability extends beyond simple denial-of-service scenarios, as it can be exploited in various contexts where BFD library functions are invoked to process untrusted binary input. Attackers could leverage this flaw by crafting specially formatted ELF files designed to trigger the excessive memory allocation during note parsing operations. This vulnerability affects systems running GNU Binutils 2.32 and potentially earlier versions, making it particularly concerning given the widespread use of these tools in development environments, build systems, and security analysis tools. The vulnerability aligns with CWE-770, which categorizes excessive resource consumption, and represents a classic example of a resource exhaustion attack that can be used to disrupt services or potentially enable more sophisticated exploitation techniques.
Systems utilizing the affected BFD library are vulnerable to several attack vectors where malicious ELF files could be processed, including automated build systems that scan or analyze binary artifacts, security tools that perform file analysis, and any application that relies on BFD for binary processing. The vulnerability is particularly dangerous in environments where automated processing of user-provided or third-party binaries occurs, as it could enable attackers to cause system instability or resource exhaustion across multiple applications. Mitigation strategies should focus on updating to patched versions of GNU Binutils, implementing input validation measures, and employing sandboxing techniques when processing untrusted binary content. From an ATT&CK framework perspective, this vulnerability maps to techniques involving resource exhaustion and privilege escalation through software exploitation, potentially enabling attackers to gain unauthorized access or cause persistent service disruptions in affected systems.