Deserialization Insecure

When you're staring at a `rememberMe` cookie that starts with `rO0AB` or a POST body with `O:8:"ClassName"`, this is the playbook you load. It walks through traffic fingerprinting for Java, PHP, and Python deserialization, then covers the actual exploit chains: ysoserial for Java gadgets (CommonsCollections, Spring, the whole roster), PHPGGC for PHP magic methods, Shiro rememberMe with hardcoded keys, WebLogic T3, and Phar wrapper tricks. The URLDNS probe for safe confirmation is smart. The gadget chain version matrix saves you from trial and error hell. It knows the JDK 8u191 cutoff where remote class loading dies and you pivot to serialized gadgets over LDAP. This is the difference between finding `readObject()` and actually popping a shell.

skills.sh installs: 3.8K
GitHub stars: 2.6K
last updated: Aug 21, 2026

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Install

$ npx -y skills add yaklang/hack-skills --skill deserialization-insecure --agent claude-code

Installs into .claude/skills of the current project.

Files

SKILL: Insecure Deserialization — Expert Attack Playbook

AI LOAD INSTRUCTION: Expert deserialization techniques across Java, PHP, and Python. Covers gadget chain selection, traffic fingerprinting, tool usage (ysoserial, PHPGGC), Shiro/WebLogic/Commons Collections specifics, Phar deserialization, and Python pickle abuse. Base models often miss the distinction between finding the sink and finding a usable gadget chain.

0. RELATED ROUTING

jndi-injection when deserialization leads to JNDI lookup (e.g., post-JDK 8u191 bypass via LDAP → deserialization)
unauthorized-access-common-services when the deserialization endpoint is an exposed management service (RMI Registry, T3, AJP)
ghost-bits-cast-attack when a WAF blocks your BCEL ClassLoader or Fastjson @type payload — Ghost Bits wraps each bytecode byte in a Unicode char whose low 8 bits match, yielding a payload the WAF cannot fingerprint