ssrf-ip-filter-bypass SKILL.md skillB
ssrf-ip-filter-bypass from dreadnode/capabilities is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add dreadnode/capabilities/ssrf-ip-filter-bypass@git:20260504.2a64374Pins git:20260504.2a64374 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- B, 16 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- dreadnode/capabilities
- Path
capabilities/web-security/skills/ssrf-ip-filter-bypass/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260504.2a64374, committed May 4, 2026
- Size
- 7,174 bytes
- Repository stars
- 22
- License
- MIT
Bypass IP-based SSRF filters using hex/octal/decimal encoding of blocked addresses. Use when SSRF endpoint has string-based IP validation blocking cloud metadata or internal ranges.
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
# SSRF IP Filter Bypass via Address Encoding ## Pattern - SSRF endpoint exists but blocks known internal IPs (169.254.169.254, 127.0.0.1, 10.x, 172.16.x) - Filter is string/regex-based (not post-resolution IP comparison) - OS network stack resolves encoded IPs to their real addresses ## Core Technique Encode blocked IP addresses in alternative representations that bypass string filters but resolve identically at the network layer. ### AWS Metadata (169.254.169.254) — All Variants | Variant | Value | Bypasses | |---|---|---| | First octet hex | `0xa9.254.169.254` | `^169\.` regex filters | | All octets hex | `0xa9.0xfe.0xa9.0xfe` | Any dotted-decimal regex | | Full hex integer | `0xA9FEA9FE` | Dotted-notation filters | | Decimal integer | `2852039166` | Dotted-notation filters | | Octal | `0251.0376.0251.0376` | Decimal-only filters | | Mixed | `0xa9.254.0xa9.254` | Partial regex filters | | IPv6-mapped | `[::ffff:a9fe:a9fe]` | IPv4-only filters | | IPv6 shorthand | `[::ffff:169.254.169.254]` | IPv4-only filters | ### Localhost (127.0.0.1) — All Variants | Variant | Value | Bypasses | |---|---|---| | Hex | `0x7f.0.0.1` | `^127\.` regex | …
Read the whole file at its exact version.
How to install
mdr add dreadnode/capabilities/ssrf-ip-filter-bypass@sha256:7229a8595803c5c3The line at the top of this page pins the label git:20260504.2a64374, 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_w6ubg36ijlxxu5ov)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on May 4, 2026.
Audit of the latest version
- fail: No link to a raw IP address (matched: http://169.254.169.254)
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (7174 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 curl or wget piped into a shell
- 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 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
dreadnode/capabilities · 22 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_w6ubg36ijlxxu5ov GET https://markdownregistry.com/api/v1/resolve?ref=dreadnode/capabilities/ssrf-ip-filter-bypass GET https://markdownregistry.com/api/v1/blob/7229a8595803c5c3ac32ebdaa12c39d220268441afb70306c3265041e12f1eeb
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.