CVE-2018-20623 in binutils
Summary
by MITRE
In GNU Binutils 2.31.1, there is a use-after-free in the error function in elfcomm.c when called from the process_archive function in readelf.c via a crafted ELF file.
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Analysis
by VulDB Data Team • 05/06/2025
The vulnerability identified as CVE-2018-20623 represents a critical use-after-free condition within GNU Binutils version 2.31.1, specifically affecting the error handling mechanisms during ELF file processing. This flaw exists in the elfcomm.c file where the error function is invoked from the process_archive function located in readelf.c, creating a scenario where memory that has been freed is subsequently accessed. The vulnerability manifests when processing specially crafted ELF files that trigger the problematic code path, making it particularly dangerous in environments where untrusted binary data is processed.
The technical implementation of this vulnerability stems from improper memory management within the ELF file parsing routines of the readelf utility. When the process_archive function encounters a malformed archive structure within an ELF file, it calls the error function in elfcomm.c which contains a use-after-free condition. The flaw occurs because the code frees memory resources but continues to reference them during error reporting, or the memory management logic fails to properly track resource allocation and deallocation sequences. This type of vulnerability falls under CWE-416, which specifically addresses the use of freed memory conditions in software systems. The vulnerability is particularly insidious because it can be triggered through normal file processing operations, making it difficult to detect and prevent.
The operational impact of CVE-2018-20623 extends beyond simple program crashes, as it creates potential for remote code execution in scenarios where the affected system processes untrusted ELF files. Attackers could craft malicious ELF files designed to exploit this vulnerability during normal file analysis operations, potentially leading to arbitrary code execution with the privileges of the user running the readelf utility. The vulnerability affects systems that utilize GNU Binutils for ELF file analysis, which includes development environments, system administration tools, and security analysis platforms. This makes the impact widespread across various computing environments where ELF file processing is common.
Mitigation strategies for this vulnerability should focus on immediate patching of GNU Binutils to version 2.32 or later, which contains the necessary memory management fixes. Organizations should also implement strict file validation procedures for ELF files, particularly when processing untrusted inputs, and consider sandboxing file analysis operations to limit potential damage from exploitation attempts. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for dynamic resolution and T1203 for Exploitation for Client Execution, highlighting the need for defensive measures that monitor and control file processing activities. Additionally, system administrators should consider implementing automated vulnerability scanning tools that can detect and alert on potentially malicious ELF file structures before they can be processed by vulnerable versions of readelf.