CVE-2018-19353 in libansilove
Summary
by MITRE
The ansilove_ansi function in loaders/ansi.c in libansilove 1.0.0 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a crafted file.
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Analysis
by VulDB Data Team • 04/14/2020
The vulnerability identified as CVE-2018-19353 resides within the libansilove library version 1.0.0, specifically in the ansilove_ansi function located in the loaders/ansi.c file. This library is designed to handle ANSI art file format processing, which is commonly used for creating and displaying text-based graphics in terminal environments. The flaw manifests when the library processes specially crafted ANSI files that contain malformed data structures, leading to improper memory handling during the parsing process. The vulnerability represents a classic out-of-bounds read condition that occurs when the function fails to properly validate input data before attempting to access memory locations beyond the allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate input validation within the ansilove_ansi function, which processes ANSI art files without sufficient bounds checking mechanisms. When a maliciously crafted file is fed to the library, the function attempts to read data from memory locations that have not been properly allocated or validated, resulting in an out-of-bounds memory access. This type of flaw falls under CWE-125, which specifically addresses out-of-bounds read vulnerabilities, and represents a direct violation of secure coding practices that mandate proper input validation and memory boundary checking. The function's failure to implement proper bounds checking allows attackers to manipulate the program flow by providing carefully constructed input that triggers memory access violations.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates potential attack vectors for more sophisticated exploitation attempts. Remote attackers can leverage this flaw to cause application crashes, leading to service disruption for systems relying on libansilove for ANSI art processing. The vulnerability is particularly concerning in environments where the library is used for processing untrusted input, such as web applications, file upload systems, or content management platforms that handle user-generated ANSI art files. Systems utilizing this library for automated processing of user submissions become vulnerable to persistent denial of service attacks, where attackers can repeatedly submit malicious files to exhaust system resources or cause application instability. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how seemingly benign file format processing can become a significant security risk.
Mitigation strategies for CVE-2018-19353 should focus on immediate patching of the libansilove library to version 1.1.0 or later, which contains the necessary fixes for the out-of-bounds read condition. Organizations should implement input validation measures at the application level, ensuring that all files processed through the library undergo thorough sanitization before being passed to the ansilove_ansi function. Additionally, deployment of intrusion prevention systems and network monitoring tools can help detect anomalous file processing patterns that may indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date third-party libraries and implementing robust memory safety practices in software development, particularly for applications handling file format processing. Security teams should also consider implementing sandboxing mechanisms for file processing tasks and establishing automated vulnerability scanning processes to identify similar issues in other libraries and dependencies.