Fastjson 1.2.43 Remote Code Execution Vulnerability Scanner

Fastjson is a popular JSON parsing library used by Java applications to serialize and deserialize JSON data efficiently. It is known for its high performance and is widely used in various Java-based projects, including web services, APIs, and cloud applications. Fastjson's ability to handle large sets of data quickly makes it a preferred choice for developers working in high-demand environments. The library's versatility allows it to be integrated into nearly any Java application, making data manipulation and transmission seamless. However, specific versions like 1.2.43 have been identified to contain vulnerabilities that can significantly compromise application security.

The Fastjson 1.2.43 version is vulnerable to a critical deserialization issue that allows attackers to execute arbitrary code remotely. This vulnerability stems from the library's handling of JSON data containing Java class type information, enabling an attacker to inject malicious payloads. By exploiting this flaw, an attacker can remotely execute code on the server hosting the vulnerable application, potentially gaining full control over the system. The CVSS score of 10 highlights the severe impact of this vulnerability, emphasizing the need for immediate remediation.

The exploit involves crafting a malicious JSON payload that includes the @type key to specify a Java class that can execute code upon deserialization. The payload directs Fastjson to deserialize a class that triggers an RMI (Remote Method Invocation) call to an attacker-controlled server. This action can result in the execution of arbitrary code supplied by the attacker, compromising the security of the application and the underlying system. The vulnerability specifically targets how Fastjson processes certain JSON requests, failing to adequately validate or restrict the types of classes that can be instantiated and executed.

Exploiting this vulnerability can lead to several adverse outcomes, including unauthorized access to sensitive data, system compromise, and the potential spread of malware within the network. Attackers can leverage the compromised system to conduct further attacks, escalate privileges, or disrupt operations. Given the nature of remote code execution, the impact is often severe, leading to significant operational and reputational damage for affected organizations.

Security for Everyone provides a cutting-edge platform to identify and mitigate vulnerabilities like the Fastjson 1.2.43 RCE flaw. Our comprehensive scanning solutions enable users to detect security weaknesses effectively, offering detailed reports and practical remediation advice. By joining Security for Everyone, you gain access to continuous security monitoring and expert insights, helping to protect your digital assets against emerging threats. Embrace proactive cybersecurity management with our user-friendly tools and safeguard your applications from critical vulnerabilities.

References

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