CVE-2022-46440 in ttftool
Summary
by MITRE • 02/24/2023
ttftool v0.9.2 was discovered to contain a segmentation violation via the readU16 function at ttf.c.
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Analysis
by VulDB Data Team • 03/24/2023
The vulnerability identified as CVE-2022-46440 affects ttftool version 0.9.2, a tool designed for manipulating TrueType font files. This issue manifests as a segmentation fault occurring within the readU16 function implementation in the ttf.c source file, representing a critical memory access violation that can lead to application crashes or potentially more severe consequences. The flaw demonstrates a classic buffer overread condition where the tool attempts to read 16-bit unsigned integers from memory locations that may not contain sufficient data, leading to undefined behavior and system instability.
The technical implementation of this vulnerability stems from inadequate bounds checking within the readU16 function, which is responsible for extracting 16-bit values from font data structures. When processing malformed or truncated font files, the function fails to validate that sufficient data remains in the input buffer before attempting to read from memory locations. This condition falls under the CWE-129 weakness category, specifically addressing improper validation of array indices and buffer overreads that can result in memory corruption. The vulnerability represents a direct violation of secure coding principles and demonstrates the importance of robust input validation in file processing utilities.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be exploited in various attack scenarios including denial of service attacks against systems that rely on ttftool for font processing or automated font validation tasks. Attackers could craft malicious font files designed to trigger the segmentation fault, potentially causing cascading failures in applications that depend on this tool for font manipulation. The vulnerability also presents a potential vector for more sophisticated attacks if the memory corruption can be leveraged to achieve arbitrary code execution, particularly in environments where ttftool is executed with elevated privileges or integrated into automated processing pipelines.
Mitigation strategies for CVE-2022-46440 should focus on immediate remediation through software updates to ttftool version 0.9.3 or later, which contains the necessary patches to address the buffer overread condition. System administrators should implement input validation measures to sanitize font files before processing, particularly in automated environments where untrusted input is common. The fix typically involves adding proper bounds checking to ensure that sufficient data exists before attempting to read from memory locations, aligning with the ATT&CK technique T1203 for exploitation of input validation vulnerabilities. Organizations should also consider implementing sandboxing mechanisms for font processing utilities to limit the potential impact of similar vulnerabilities in the future, as recommended by the MITRE ATT&CK framework for defensive measures against memory corruption attacks.