Fastjson 1.2.42 Remote Code Execution Vulnerability Scanner

Fastjson is a popular JSON processing library in Java, known for its high performance and ease of use. It's commonly used in applications for parsing and generating JSON data due to its fast processing speed and extensive feature set. Fastjson is integrated into a wide variety of Java-based applications, ranging from web applications to microservices, due to its ability to quickly handle large volumes of data. The library plays a crucial role in data interchange and API responses in modern software development. However, specific versions like 1.2.42 have vulnerabilities that pose serious security risks.

Fastjson version 1.2.42 contains a critical deserialization vulnerability that allows for remote code execution. This flaw enables attackers to execute arbitrary code on the affected system by sending specially crafted JSON payloads. The vulnerability exploits the library's deserialization process, where untrusted JSON data can be used to instantiate and execute Java objects. The high severity of this issue, underscored by its CVSS score of 10, makes it imperative for developers to address this vulnerability in their applications.

The vulnerability specifically targets Fastjson's feature that automatically deserializes JSON data containing Java class type information. By manipulating this feature, an attacker can construct a JSON payload that includes a reference to a malicious Java class. This class can then perform arbitrary actions when deserialized by Fastjson. The exploit uses the @type keyword in the JSON payload to specify a malicious Java class, tricking the application into executing unintended operations. This process bypasses normal application safeguards, leading to unauthorized remote code execution.

If exploited, this vulnerability can have devastating effects, including unauthorized access and control over the affected system, data theft, introduction of malware, and disruption of services. Attackers can use the compromised system to launch further attacks within the network, potentially leading to a broader security breach. The ability to execute code remotely without authentication grants attackers a high level of control, making this vulnerability a critical threat to any system using the vulnerable Fastjson version.

Security for Everyone offers a comprehensive solution for detecting and mitigating vulnerabilities like the RCE in Fastjson 1.2.42. Our platform's advanced scanning capabilities enable users to identify vulnerabilities across their digital assets, providing detailed insights and actionable remediation strategies. By joining our platform, users gain access to continuous monitoring and expert guidance, ensuring their systems remain secure against evolving threats. Protect your applications from critical vulnerabilities and enhance your cybersecurity posture with Security for Everyone.

References

• https://github.com/tdtc7/qps/tree/4042cf76a969ccded5b30f0669f67c9e58d1cfd2/Fastjson
• https://github.com/wyzxxz/fastjson_rce_tool