CVE-2023-4043 in Parsson
Summary
by MITRE • 11/03/2023
In Eclipse Parsson before versions 1.1.4 and 1.0.5, Parsing JSON from untrusted sources can lead malicious actors to exploit the fact that the built-in support for parsing numbers with large scale in Java has a number of edge cases where the input text of a number can lead to much larger processing time than one would expect.
To mitigate the risk, parsson put in place a size limit for the numbers as well as their scale.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/30/2023
The vulnerability identified as CVE-2023-4043 affects Eclipse Parsson versions prior to 1.1.4 and 1.0.5, representing a significant security concern in JSON parsing operations. This flaw specifically targets the handling of numeric values within JSON documents sourced from untrusted origins, creating potential attack vectors for malicious actors seeking to exploit computational resource exhaustion. The vulnerability stems from the inherent characteristics of Java's built-in number parsing mechanisms, which exhibit unpredictable performance behaviors when processing numbers with exceptionally large scales.
The technical implementation of this vulnerability exploits edge cases in how Java handles numeric representations during JSON parsing operations. When parsing numbers with extremely large scale values, the parsing algorithm can experience exponential increases in processing time, creating a denial of service condition. This occurs because the underlying Java number parsing routines do not adequately constrain the computational resources required for processing such inputs, leading to potential system resource exhaustion. The vulnerability manifests when attackers supply JSON data containing numbers with unusually high scale factors, causing the parser to consume disproportionate amounts of CPU cycles and memory resources.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it can effectively render applications unusable by consuming all available processing resources. Attackers can craft malicious JSON payloads that, when processed by vulnerable Parsson versions, trigger extended parsing times that can last for minutes or even hours, depending on the scale of the input data. This behavior directly aligns with attack patterns described in the ATT&CK framework under process injection and resource exhaustion techniques, where adversaries manipulate system resources to achieve their objectives. The vulnerability particularly affects applications that process untrusted JSON input from external sources, making it a critical concern for web services, APIs, and any system relying on JSON parsing for data exchange.
The mitigation strategy implemented by the Parsson development team addresses the core issue through the introduction of size limits for both numeric values and their scale parameters. This approach directly corresponds to CWE-770, which addresses the allocation of resources without proper limits or constraints. By establishing boundaries on acceptable numeric scale and magnitude, the fix prevents the exploitation of the edge cases that previously led to excessive processing times. The solution represents a defensive programming approach that aligns with industry best practices for preventing resource exhaustion attacks, ensuring that even malformed input cannot cause the system to consume disproportionate computational resources. This mitigation effectively closes the attack surface while maintaining compatibility with legitimate JSON parsing requirements.