CVE-2021-42692 in tinytoml
Summary
by MITRE • 05/26/2022
There is a stack-overflow vulnerability in tinytoml v0.4 that can cause a crash or DoS.
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Analysis
by VulDB Data Team • 05/30/2022
The stack-overflow vulnerability identified in tinytoml v0.4 represents a critical security flaw that can be exploited to cause application crashes or denial of service conditions. This vulnerability specifically affects the tinytoml library, which is a lightweight toml parser written in c++ and commonly used in applications that require toml configuration file parsing. The issue manifests when the library processes malformed or specially crafted toml input data that triggers improper stack memory handling during parsing operations. The vulnerability stems from inadequate input validation and bounds checking within the parsing functions, allowing malicious input to overflow stack buffers and potentially execute arbitrary code or cause the application to terminate unexpectedly.
The technical implementation of this vulnerability involves the manipulation of toml data structures that contain nested arrays or tables with excessive nesting levels or malformed syntax patterns. When tinytoml attempts to parse such inputs, the recursive parsing functions consume stack space without proper bounds checking, leading to stack buffer overflow conditions. This type of vulnerability falls under the common weakness enumeration category of CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data to a buffer located on the stack and overflows the buffer's boundaries. The vulnerability is particularly concerning because toml files are often used for configuration management in critical applications, making them attractive targets for attackers seeking to disrupt system operations.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable more sophisticated attack vectors. An attacker who can control the toml input processed by an application using tinytoml v0.4 could exploit this vulnerability to cause denial of service against the targeted application, effectively rendering it unavailable to legitimate users. In scenarios where the vulnerable application runs with elevated privileges or handles sensitive data, the potential for further exploitation increases significantly. The vulnerability demonstrates how seemingly benign configuration file parsing operations can become attack surfaces when proper input validation and memory management practices are not implemented. This aligns with the attack pattern described in the mitre att&ck framework under the technique of privilege escalation through software vulnerabilities, where attackers leverage library flaws to gain unauthorized system access or cause service disruption.
Mitigation strategies for this vulnerability primarily focus on immediate remediation through version updates to tinytoml v0.5 or later, which contains the necessary patches to address the stack overflow conditions. Organizations should conduct comprehensive vulnerability assessments to identify all applications using the vulnerable library and prioritize their remediation efforts. Additionally, implementing input validation mechanisms at the application level can provide additional defense-in-depth measures, ensuring that toml inputs are properly sanitized before being passed to the parsing library. The vulnerability also underscores the importance of using memory-safe programming practices and conducting regular security code reviews, particularly for libraries that handle external data parsing operations. System administrators should monitor for any applications that might be using vulnerable versions of tinytoml and implement automated patch management procedures to ensure timely remediation across all affected systems.