Agent skill · security · yaklang
deserialization-insecure
Insecure deserialization playbook. Use when Java, PHP, or Python applications deserialize untrusted data via ObjectInputStream, unserialize, pickle, or similar mechanisms that may lead to RCE, file access, or privilege escalation.
Why this skill is useful
Adds detailed attack techniques, gadget chains, and specific tool commands for exploiting insecure deserialization vulnerabilities that are not commonly known.
What it needs
Requires java installed locally. About 9k tokens when loaded. Last updated 2026-06-16. 1,563 stars on the source repository.
What this skill does
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 Advanced Reference Also load JAVAGADGETCHAINS.md when you need: Java gadget chain version compatibility matrix (CommonsCollections 1–7, CommonsBeanutils, Spring, JDK-only, Groovy, Hibernate, ROME, C3P0, etc.) SnakeYAML gadget (ScriptEngineManager/URLClassLoader) with exploit JAR structure Hessian/Kryo/Avro/XStream deserialization patterns and traffic fingerprints .NET ViewState deserialization (machineKey requirement, ViewState forgery with ysoserial.net, Blacklist3r) Ruby YAML.load vs YAML.safeload exploitation with version-specific chains Detection fingerprints: magic bytes table by format (Java AC ED, .NET AAEAAD, Python pickle 80 0N, PHP O:, Ruby 04 08) --- 1. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills yaklang/deserialization-insecure