CVE-2018-20002 in binutils
Summary
by MITRE
The _bfd_generic_read_minisymbols function in syms.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.31, has a memory leak via a crafted ELF file, leading to a denial of service (memory consumption), as demonstrated by nm.
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Analysis
by VulDB Data Team • 06/13/2023
The vulnerability identified as CVE-2018-20002 resides within the Binary File Descriptor (BFD) library, a core component of GNU Binutils that provides standardized interfaces for reading and writing binary files. This memory leak occurs specifically in the _bfd_generic_read_minisymbols function located in syms.c, where the library fails to properly release allocated memory resources when processing malformed ELF files. The flaw affects version 2.31 of the BFD library and demonstrates a critical weakness in memory management that can be exploited through carefully crafted input files.
The technical implementation of this vulnerability involves the improper handling of memory allocation during symbol table processing within ELF format files. When the nm utility processes a maliciously constructed ELF file, the _bfd_generic_read_minisymbols function allocates memory for symbol information but fails to deallocate it properly upon encountering certain malformed structures within the file. This memory management failure results in progressive memory consumption that continues with each processed file, ultimately leading to system resource exhaustion. The vulnerability represents a classic example of a memory leak as classified by CWE-401, which specifically addresses insufficient memory deallocation in software systems.
The operational impact of this vulnerability extends beyond simple resource consumption, creating significant denial of service conditions that can affect systems relying on nm or other tools that utilize the BFD library for binary analysis. Attackers can exploit this weakness by preparing specially crafted ELF files that trigger the memory leak when processed by nm, causing progressive memory degradation that may eventually crash the system or render it unresponsive. The vulnerability affects systems where nm is frequently used for binary analysis, particularly in development environments, security tools, and automated build systems that process multiple binary files.
Mitigation strategies for CVE-2018-20002 primarily focus on immediate patching of affected systems with updated versions of GNU Binutils that contain the necessary memory management fixes. Organizations should prioritize updating their BFD library components to versions that address this memory leak vulnerability, as the flaw can be exploited remotely through file processing operations. Additionally, system administrators should implement monitoring for abnormal memory consumption patterns when processing binary files, particularly in automated environments where nm or similar tools may process untrusted input. The ATT&CK framework categorizes this vulnerability under privilege escalation and resource exhaustion techniques, as it can be leveraged to consume system resources and potentially disrupt normal operations through sustained memory consumption. Organizations should also consider implementing input validation and sanitization measures for binary file processing to reduce the attack surface and prevent exploitation of similar memory management flaws in other components.