CVE-2023-49462: Struktur Libheif Buffer Overflow Flaw

CVE-2023-49462 Overview

CVE-2023-49462 is a segmentation violation vulnerability discovered in libheif v1.17.5, a popular open-source library for reading and writing HEIF (High Efficiency Image File Format) and AVIF image files. The vulnerability exists within the EXIF parsing component located in /libheif/exif.cc. When processing maliciously crafted image files, the library can trigger a segmentation fault, potentially leading to denial of service or arbitrary code execution.

Critical Impact

This vulnerability allows remote attackers to potentially crash applications using libheif or execute arbitrary code by convincing users to open specially crafted HEIF/AVIF image files.

Affected Products

• struktur libheif version 1.17.5
• Applications and services that integrate libheif for HEIF/AVIF image processing
• Image viewers, converters, and media applications using the vulnerable library version

Discovery Timeline

• 2023-12-07 - CVE-2023-49462 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-49462

Vulnerability Analysis

The vulnerability is classified as a memory corruption issue that manifests as a segmentation violation (segfault) during EXIF metadata processing. The flaw resides in the exif.cc component of libheif, which handles the parsing of Exchangeable Image File Format (EXIF) metadata embedded within HEIF images.

When the EXIF parser encounters malformed or specially crafted metadata structures, it fails to properly validate memory boundaries before accessing data. This results in the application attempting to read from or write to invalid memory addresses, causing a segmentation fault. The network attack vector indicates that exploitation can occur through remote delivery of malicious image files via web pages, email attachments, or other network-based content delivery mechanisms.

Root Cause

The root cause is improper memory access handling within the EXIF parsing routines in /libheif/exif.cc. The code fails to adequately validate buffer boundaries and pointer references when processing EXIF metadata structures, leading to out-of-bounds memory access when parsing malformed input data. This type of vulnerability typically occurs when array indices or pointer arithmetic are not properly bounds-checked against the actual allocated memory size.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker would need to craft a malicious HEIF or AVIF image file containing specially designed EXIF metadata that triggers the segmentation fault. The attack scenario involves:

1. Attacker creates a malformed HEIF/AVIF image with crafted EXIF data
2. Victim downloads or receives the malicious image file
3. When the victim's application attempts to parse the image using libheif, the vulnerable EXIF parsing code is triggered
4. The segmentation fault occurs, potentially crashing the application or enabling further exploitation

The vulnerability affects any application that uses libheif to process untrusted image files, including image viewers, photo management software, web browsers with HEIF support, and content management systems.

Detection Methods for CVE-2023-49462

Indicators of Compromise

• Unexpected application crashes when opening or processing HEIF/AVIF image files
• Segmentation fault errors in application logs referencing libheif or EXIF processing components
• Abnormal memory access patterns or core dumps indicating invalid pointer dereferences
• Presence of unusually structured or malformed HEIF/AVIF files with anomalous EXIF metadata

Detection Strategies

• Monitor system logs for segmentation fault signals (SIGSEGV) associated with applications using libheif
• Implement file integrity monitoring for applications that process image files
• Deploy application-level sandboxing to detect and contain abnormal memory access attempts
• Use memory safety tools like AddressSanitizer during development and testing to identify similar issues

Monitoring Recommendations

• Enable crash reporting and analysis for applications using libheif to detect exploitation attempts
• Monitor for unusual patterns in image file uploads or downloads that may indicate delivery of malicious payloads
• Implement logging for EXIF parsing operations to identify anomalous metadata structures
• Consider deploying endpoint detection capabilities that can identify memory corruption exploitation attempts

How to Mitigate CVE-2023-49462

Immediate Actions Required

• Upgrade libheif to a patched version beyond 1.17.5 that addresses this vulnerability
• Audit applications and dependencies to identify all instances of libheif usage
• Implement input validation for image files before processing with libheif
• Consider sandboxing or isolating image processing operations to limit impact of potential exploitation

Patch Information

Users should upgrade to a patched version of libheif. The vulnerability has been tracked and discussed in the libheif GitHub issue tracker. Review the issue discussion for specific patch commits and updated versions that address this security flaw. Ensure all applications and libraries that depend on libheif are updated accordingly.

Workarounds

• Restrict processing of HEIF/AVIF images from untrusted sources until patching is complete
• Implement content-type filtering to block HEIF/AVIF files at network boundaries if not required
• Run libheif-dependent applications with reduced privileges or in sandboxed environments
• Consider using alternative image processing libraries for handling untrusted image content temporarily

# Check installed libheif version
pkg-config --modversion libheif

# Update libheif on Debian/Ubuntu-based systems
sudo apt update && sudo apt upgrade libheif-dev

# Update libheif on macOS with Homebrew
brew upgrade libheif

# Verify the update was applied
pkg-config --modversion libheif