CVE-2022-1622: Libtiff Out-of-Bounds Read DOS Vulnerability

CVE-2022-1622 Overview

CVE-2022-1622 is an out-of-bounds read vulnerability affecting the LibTIFF library, specifically in the LZWDecode function located in libtiff/tif_lzw.c at line 619. This memory safety issue allows attackers to cause a denial-of-service condition by crafting a malicious TIFF file that triggers improper memory access during image decompression.

LibTIFF is a widely-used open-source library for reading and writing TIFF (Tagged Image File Format) images, integrated into numerous operating systems and applications including Apple's iOS, macOS, tvOS, and watchOS platforms. The widespread adoption of LibTIFF across multiple vendors amplifies the potential impact of this vulnerability.

Critical Impact

Attackers can crash applications processing TIFF images, leading to denial of service across systems using LibTIFF including Apple devices, Fedora Linux, and NetApp storage systems.

Affected Products

• LibTIFF version 4.3.0 and master branch
• Fedora 35 and Fedora 36
• Apple iOS, macOS, tvOS, and watchOS (multiple versions)
• NetApp ONTAP Select Deploy Administration Utility

Discovery Timeline

• May 11, 2022 - CVE-2022-1622 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-1622

Vulnerability Analysis

The vulnerability exists within the LZW (Lempel-Ziv-Welch) decompression routine of LibTIFF. When processing a specially crafted TIFF file, the LZWDecode function fails to properly validate memory boundaries before performing read operations. This out-of-bounds read occurs because the decompression algorithm does not adequately verify that the data being accessed falls within allocated buffer limits.

The flaw is classified as CWE-125 (Out-of-bounds Read), indicating that the software reads data past the end or before the beginning of the intended buffer. While out-of-bounds reads typically do not allow code execution, they can expose sensitive memory contents or cause application crashes when accessing protected memory regions.

The local attack vector requires user interaction—specifically, a victim must open a malicious TIFF file with an application using the vulnerable LibTIFF library. This makes social engineering or drive-by download scenarios viable attack paths.

Root Cause

The root cause stems from insufficient bounds checking in the LZWDecode function within tif_lzw.c. During LZW decompression, the function processes compressed data streams without adequately validating that read operations stay within the bounds of the input buffer. When a malformed TIFF file contains corrupted or intentionally crafted LZW-compressed data, the decoder may attempt to read memory locations beyond the allocated buffer boundaries.

The fix implemented in commit b4e79bfa0c7d2d08f6f1e7ec38143fc8cb11394a adds proper boundary validation to prevent the out-of-bounds memory access during the decompression process.

Attack Vector

The attack requires local access and user interaction. An attacker must convince a user to open a maliciously crafted TIFF file using an application that relies on the vulnerable LibTIFF library for image processing. Common attack scenarios include:

The vulnerability is triggered when the LZWDecode function processes a specially crafted TIFF file containing malformed LZW-compressed image data. The malicious file causes the decoder to read beyond allocated buffer boundaries, resulting in either a crash (denial of service) or potential information disclosure from adjacent memory regions.

Given the widespread use of LibTIFF across Apple operating systems and various Linux distributions, attack surfaces include email attachments, web downloads, messaging applications, and any software that processes TIFF images.

Detection Methods for CVE-2022-1622

Indicators of Compromise

• Unexpected application crashes when processing TIFF image files
• Abnormal memory access patterns in applications using LibTIFF
• Core dumps or crash reports indicating faults in tif_lzw.c or related LibTIFF components
• Unusual TIFF files with malformed LZW compression headers

Detection Strategies

• Monitor system logs for repeated crashes in image processing applications
• Implement file integrity monitoring for TIFF files entering the environment
• Deploy endpoint detection rules targeting abnormal LibTIFF library behavior
• Use static analysis tools to identify vulnerable LibTIFF versions in deployed software

Monitoring Recommendations

• Enable crash reporting and analyze crash dumps for patterns indicating exploitation attempts
• Monitor network traffic for suspicious TIFF file transfers, particularly from untrusted sources
• Track software inventory to identify systems running vulnerable LibTIFF versions
• Implement sandbox environments for processing untrusted image files

How to Mitigate CVE-2022-1622

Immediate Actions Required

• Update LibTIFF to a patched version incorporating commit b4e79bfa0c7d2d08f6f1e7ec38143fc8cb11394a
• Apply operating system updates from Apple (see HT213443, HT213444, HT213446)
• Update Fedora systems via official package updates (see Fedora Package Announcements)
• Review the NetApp Security Advisory for ONTAP Select Deploy Administration Utility updates

Patch Information

For users compiling LibTIFF from sources, the fix is available in commit b4e79bfa0c7d2d08f6f1e7ec38143fc8cb11394a. The patch can be obtained from the official LibTIFF GitLab repository.

Apple has released security updates addressing this vulnerability across multiple platforms:

• iOS and iPadOS: See Apple Support Document HT213486
• macOS: See Apple Support Document HT213443 and HT213488
• tvOS: See Apple Support Document HT213487
• watchOS: See Apple Support Document HT213444

Fedora users should update via standard package management to receive the patched LibTIFF packages.

Workarounds

• Restrict TIFF file processing to trusted sources only until patches can be applied
• Implement application sandboxing to limit the impact of potential crashes
• Use alternative image formats (PNG, JPEG) where LZW-compressed TIFF processing is not required
• Deploy web application firewalls or email filters to block suspicious TIFF file uploads

# For users compiling LibTIFF from source, apply the fix:
git clone https://gitlab.com/libtiff/libtiff.git
cd libtiff
git checkout b4e79bfa0c7d2d08f6f1e7ec38143fc8cb11394a
./autogen.sh
./configure
make && make install