Ysoserial definition

Ysoserial is a programming tool that can be used to exploit Java deserialization vulnerabilities. It consists of modules known as playloads. These playloads generate a serialized object that invokes some action when instantiated, compromising the system or its data.

How can Ysoserial be used to compromise data?

• Access unauthorized resources
• Execute malicious code on targeted servers
• Upload malicious files

How to spot and prevent insecure data deserialization with Ysoserial

• Implement integrity checks (e.g., digital signatures) to prevent data tampering.
• Enforce strict type constraints during deserialization.
• Restrict and monitor incoming and outgoing network connectivity from servers that deserialize.
• Log deserialization exceptions and failures.

Further reading