CVE-2023-1972: GNU Binutils Buffer Overflow Vulnerability

CVE-2023-1972 Overview

A heap-based buffer overflow vulnerability was discovered in the _bfd_elf_slurp_version_tables() function within bfd/elf.c of GNU Binutils. This vulnerability occurs when parsing ELF files and can be triggered by processing a specially crafted malformed ELF binary, leading to denial of service through loss of availability.

Critical Impact

Attackers can cause application crashes and denial of service by crafting malicious ELF files that exploit improper memory handling in the version table parsing routine.

Affected Products

• GNU Binutils (all versions prior to fix)

Discovery Timeline

• 2023-05-17 - CVE CVE-2023-1972 published to NVD
• 2025-01-22 - Last updated in NVD database

Technical Details for CVE-2023-1972

Vulnerability Analysis

The vulnerability resides in the Binary File Descriptor (BFD) library, which is a core component of GNU Binutils used for processing various executable file formats. Specifically, the _bfd_elf_slurp_version_tables() function in bfd/elf.c contains a heap-based buffer overflow that can be triggered when parsing version definition entries in ELF files.

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-787 (Out-of-bounds Write). The flaw occurs due to insufficient validation of input data when processing ELF version tables, allowing an attacker to write beyond allocated buffer boundaries.

The attack requires user interaction, as the victim must be convinced to process a malicious ELF file using tools that rely on the affected BFD library, such as objdump, readelf, nm, or other binutils utilities. The impact is primarily availability-focused, potentially causing crashes in development and build environments.

Root Cause

The root cause stems from inadequate bounds checking when processing version table data in ELF binaries. The _bfd_elf_slurp_version_tables() function fails to properly validate the size and offset values from the ELF version definition structures before copying data into heap-allocated buffers. This allows crafted ELF files with manipulated version table metadata to trigger buffer overflows during parsing operations.

Attack Vector

The attack vector is network-based, where an attacker can deliver a maliciously crafted ELF file through various means such as email attachments, malicious downloads, or compromised software repositories. When a user or automated build system processes this file using any binutils tool that invokes the BFD library, the vulnerability is triggered.

The exploitation scenario involves:

1. Attacker crafts an ELF binary with malformed version definition entries
2. The crafted file contains invalid size or count values in the version table headers
3. Victim processes the file using binutils (e.g., objdump -a malicious.elf)
4. The BFD library parses the version tables without proper validation
5. Heap buffer overflow occurs, causing memory corruption and crash

The vulnerability mechanism involves improper bounds validation during ELF version table parsing. When the _bfd_elf_slurp_version_tables() function processes an ELF file, it allocates heap memory based on header values and copies version table data without adequately verifying that the source data fits within the allocated buffer. Technical details are available in the Sourceware Bug Report #30285.

Detection Methods for CVE-2023-1972

Indicators of Compromise

• Unexpected crashes of binutils tools (objdump, readelf, nm, strings) when processing ELF files
• Memory corruption errors or segmentation faults in applications linked against the BFD library
• Unusual or malformed ELF files appearing in build environments or software repositories
• Repeated denial of service conditions in CI/CD pipelines that process ELF binaries

Detection Strategies

• Deploy file integrity monitoring on critical development and build systems to detect introduction of malicious ELF files
• Implement sandboxing for binutils operations, especially in automated build pipelines
• Monitor for abnormal process terminations of binutils-related tools with memory-related exit codes
• Use address sanitizer (ASAN) builds of binutils in development environments to detect exploitation attempts

Monitoring Recommendations

• Configure crash reporting mechanisms to alert on repeated binutils tool failures
• Implement input validation for ELF files before processing in automated systems
• Monitor system logs for patterns indicating potential exploitation attempts against binutils
• Track resource usage anomalies in processes using the BFD library

How to Mitigate CVE-2023-1972

Immediate Actions Required

• Update GNU Binutils to the latest patched version available from your distribution
• Avoid processing untrusted ELF files with binutils tools until patched
• Implement file source validation in CI/CD pipelines before processing ELF binaries
• Consider using containerized or sandboxed environments for analyzing potentially malicious ELF files

Patch Information

Users should update GNU Binutils to the latest available version that includes the fix for this vulnerability. The issue has been tracked in the Sourceware Bug Report #30285. Linux distributions have released their own advisories, including Gentoo Security GLSA 202309-15 and Red Hat Bug Report #2185646. Check your distribution's package manager for available security updates.

Workarounds

• Restrict processing of ELF files to only trusted sources in development environments
• Use alternative tools for inspecting untrusted ELF binaries where possible
• Deploy application-level sandboxing (e.g., seccomp, AppArmor) around binutils usage
• Implement pre-validation of ELF file structure before passing to binutils

# Configuration example
# Update binutils on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade binutils

# Update binutils on RHEL/CentOS/Fedora systems
sudo dnf update binutils

# Update binutils on Gentoo systems
sudo emerge --sync && sudo emerge -u sys-devel/binutils