If a target application is vulnerable to the standard CommonsCollections1 chain, a pentester might generate a payload to open a calculator application (as a proof of concept) like this:
java -jar ysoserial.jar CommonsBeanutils192NOCC "CLASS:SpringInterceptorMemShell"
Ysoserial is a collection of utility programs discovered by security researchers that discover and exploit common Java libraries. When these libraries are present in a target application's classpath, they can be chained together during deserialization to execute system commands. These chains are commonly referred to as "gadget chains."
ysoserial is a Java library that provides a framework for generating and exploiting deserialization gadgets in Java. It is commonly used in penetration testing and vulnerability research. ysoserial-0.0.4-all.jar download
Are you working on a legitimate security research project or authorized penetration test?
ysoserial is designed strictly for authorized penetration testing, security research, and educational purposes. Utilizing this tool to attack computer systems without explicit, written permission from the system owner is illegal and punishable under computer crime laws globally.
Ysoserial, including the ysoserial-0.0.4-all.jar version, represents a cornerstone of Java security testing. Understanding how to properly use this tool is essential for security professionals tasked with identifying and remediating dangerous deserialization vulnerabilities. If a target application is vulnerable to the
For Blue Teams and defenders, understanding the tool's artifacts is key to detecting and blocking attacks.
For .NET environments, various payload generators target formatters like ViewState, LosFormatter, and ObjectStateFormatter.
Downloading pre-compiled JAR files from third-party sites or forums is extremely risky. Malicious actors frequently "backdoor" security tools, meaning a JAR labeled "ysoserial-0.0.4-all.jar" could infect the researcher's own machine upon execution. Always verify hashes or compile from the original source. It is commonly used in penetration testing and
This generates a payload that launches the calculator application when deserialized.
If you download a pre-compiled ysoserial-0.0.4-all.jar from a third-party repository, always verify its integrity: