CVE-2023-40745: LibTIFF Integer Overflow RCE Vulnerability

CVE-2023-40745 Overview

LibTIFF, a widely-used open-source library for reading and writing Tagged Image File Format (TIFF) files, is vulnerable to an integer overflow vulnerability. This flaw allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted TIFF image, which triggers a heap-based buffer overflow.

The vulnerability stems from improper handling of integer arithmetic operations when processing TIFF image data. When a specially crafted TIFF file is processed by the affected library, the integer overflow can lead to incorrect memory allocation sizes, ultimately resulting in a heap-based buffer overflow condition.

Critical Impact

Remote attackers can exploit this vulnerability to crash applications using LibTIFF or potentially achieve arbitrary code execution by delivering malicious TIFF images through email attachments, web downloads, or other file transfer mechanisms.

Affected Products

• LibTIFF (all vulnerable versions)
• NetApp Active IQ Unified Manager for VMware vSphere
• Fedora Linux
• Red Hat Enterprise Linux 8.0 and 9.0

Discovery Timeline

• October 5, 2023 - CVE-2023-40745 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-40745

Vulnerability Analysis

This vulnerability is classified as CWE-190 (Integer Overflow or Wraparound). The flaw occurs during arithmetic operations within LibTIFF's image processing routines. When processing certain TIFF image parameters, the library performs calculations that can result in integer overflow conditions when provided with maliciously crafted input values.

The integer overflow leads to an undersized memory allocation, which subsequently causes a heap-based buffer overflow when data is written to the allocated buffer. This memory corruption can result in application crashes (denial of service) or, in some scenarios, may be leveraged by skilled attackers to achieve code execution.

The vulnerability is exploitable via network vectors, requiring user interaction such as opening a malicious TIFF file. This attack scenario commonly manifests through phishing emails containing malicious image attachments, compromised websites serving crafted images, or document processing workflows that automatically handle TIFF files.

Root Cause

The root cause is an integer overflow vulnerability (CWE-190) in LibTIFF's image processing code. When certain arithmetic operations are performed on attacker-controlled values from the TIFF file structure, the calculations can wrap around due to integer overflow, resulting in a value smaller than expected. This undersized value is then used for memory allocation, creating a heap buffer that is too small to hold the actual data being processed.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker crafts a malicious TIFF image file containing specially designed values that trigger the integer overflow during processing. The attack scenario typically involves:

1. Attacker creates a malicious TIFF file with crafted header values designed to cause integer overflow
2. The malicious file is delivered to the victim through email, web download, or network share
3. The victim opens the file or an application automatically processes it
4. LibTIFF processes the file, triggering the integer overflow and subsequent heap buffer overflow
5. The application crashes or the attacker potentially gains code execution

The vulnerability requires no authentication and can be triggered by any application linked against the vulnerable LibTIFF library when processing untrusted TIFF images.

Detection Methods for CVE-2023-40745

Indicators of Compromise

• Unexpected application crashes when processing TIFF image files
• Memory corruption errors or segmentation faults in applications using LibTIFF
• Unusual TIFF files with abnormal or suspicious header values appearing in system logs
• Heap corruption detected by memory debugging tools during TIFF processing

Detection Strategies

• Deploy endpoint detection solutions capable of identifying heap overflow exploitation attempts
• Monitor for abnormal process behavior when image processing applications handle TIFF files
• Implement file integrity monitoring on systems that process TIFF images from untrusted sources
• Use application sandboxing to contain potential exploitation attempts

Monitoring Recommendations

• Enable crash dump collection and analysis for applications using LibTIFF
• Monitor system logs for repeated application crashes related to image processing
• Implement network monitoring to detect delivery of potentially malicious TIFF files
• Configure SIEM alerts for patterns consistent with image-based exploitation attempts

How to Mitigate CVE-2023-40745

Immediate Actions Required

• Update LibTIFF to the latest patched version on all affected systems
• Apply vendor-specific patches from Red Hat, Fedora, and NetApp as available
• Restrict processing of TIFF files from untrusted sources until patches are applied
• Implement application sandboxing for image processing workflows

Patch Information

Patches are available through the respective vendor channels. Red Hat has released security advisory RHSA-2024:2289 addressing this vulnerability for Enterprise Linux. Additional technical details are available through Red Hat's CVE page and Bug Report #2235265. NetApp users should consult Security Advisory NTAP-20231110-0005 for product-specific guidance.

System administrators should prioritize patching systems that handle TIFF files from external or untrusted sources, including document management systems, image processing servers, and end-user workstations.

Workarounds

• Disable automatic TIFF processing in email clients and web browsers
• Implement network-level filtering to quarantine TIFF files for scanning before delivery
• Use application whitelisting to restrict which applications can process TIFF files
• Configure file type policies to route TIFF files through secure processing pipelines

# Check installed LibTIFF version on Linux systems
rpm -qa | grep libtiff
dpkg -l | grep libtiff

# Update LibTIFF on Red Hat/CentOS/RHEL
sudo yum update libtiff

# Update LibTIFF on Debian/Ubuntu
sudo apt-get update && sudo apt-get upgrade libtiff5

# Update LibTIFF on Fedora
sudo dnf update libtiff