SSRF playbook. Use when the server fetches URLs, resolves hostnames, imports remote content, or can be driven toward internal networks, cloud metadata, or secondary protocols.

SKILL: Server Side Request Forgery (SSRF) — Expert Attack Playbook AI LOAD INSTRUCTION : Expert SSRF techniques. Covers URL filter bypass, cloud metadata endpoints, protocol exploitation, blind SSRF detection, and chaining to RCE. Base models know basic 169.254.169.254 — this file covers what they miss. For real world CVE chains, DNS Rebinding deep dives, K8s SSRF, and SSRF → Redis → RCE full exploitation, load the companion [SCENARIOS.md](./SCENARIOS.md). 0. QUICK START Extended Scenarios Also load [SCENARIOS.md](./SCENARIOS.md) when you need: WebLogic SSRF (CVE 2014 4210) — uddiexplorer/SearchPublicRegistries.jsp + operator parameter + %0D%0A CRLF to inject Redis commands SSRF → internal Redis → write crontab reverse shell complete payload chain DNS Rebinding deep dive — TTL=0 trick, initial legit→second internal resolution, rbndr.us service Kubernetes SSRF (CVE 2020 8555) and bypass (CVE 2020 8562) via DNS rebinding SSRF through PDF/screenshot generators — <iframe and <img in HTML to PDF Gopher protocol full TCP injection — Redis, MySQL, FastCGI payloads via Gopherus URL parser confusion for filter bypass — @ , \@ , %00@ , IPv6 mapped IPv4 Advanced Reference Also load [URL PARSER TRICKS.md](./URL PARSER TRICKS.md) when you need: URL parser differential table: Python urllib vs requests vs Java URL vs PHP parse url vs Node url.parse vs Go net/url Full cloud metadata endpoint catalog (AWS IMDSv1/v2, GCP, Azure, DigitalOcean, Alibaba Cloud, Oracle Cloud, Kubernetes, Hetzner, OpenStack) gopher:// payload recipes for Redis, MySQL, SMTP, FastCGI, Memcached (with encoding rules) DNS Rebinding detailed attack flow with TTL manipulation and TOCTOU analysis PDF/wkhtmltopdf/WeasyPrint/Chrome headless/PhantomJS SSRF patterns and exfiltration techniques If you just found a parameter that fetches a URL, perform first pass confirmation here directly. First pass payloads Host validation bypass families Validation Type Try blocks localhost string 127.0.0.1 , 127.1 , [::1] blocks direct IP only internal DNS name, decimal/octal/hex IP forms allowlist by prefix username part, subdomain confusion, redirect chain follows redirects benign external URL redirecting to internal target parses once, fetches twice mixed encoding or DNS rebinding style targets Protocol routing Goal Protocol / Target cloud credentials metadata HTTP endpoints internal HTTP admin http://127.0.0.1:port/ Redis / raw TCP style abuse gopher:// local file read candidate file:// dictionary / banner tests dict:// 1. FINDING SSRF SURFACE Look for any parameter containing DNS names, IP addresses, or URLs : Less obvious SSRF vectors : PDF/screenshot generation (URL to capture) Webhook configuration fields Import/export via URL (CSV import, RSS/Atom feeds) OAuth redirect URI (sometimes triggers server side fetch) X Forwarded Host / X Real IP headers in proxy chains XML DOCTYPE with external entity ( file:// , http:// ) GraphQL @link directive (federation) Content Type: text/html pages parsed for <link preload headers 2. BASIC CONFIRMATION METHODOLOGY 3. CLOUD METADATA ENDPOINTS — MUST TRY AWS EC2 IMDSv1 (no auth required — critical) AWS IMDSv2 (token required — but check if SSRF can GET the token) If SSRF supports custom headers → full IMDSv2 bypass . Google Cloud Azure Alibaba Cloud Kubernetes Service Account 4. IP ADDRESS FILTER BYPASS TECHNIQUES When 169.254.169.254 , 127.0.0.1 , localhost are blocked: Localhost Variants 169.254.169.254 Variants Private Network Ranges Bypass Filter via DNS Input If filter checks DNS resolved IP (not hostname): Use DNS rebinding: initial lookup returns valid IP → passes filter → second request returns internal IP. 5. URL SCHEME ATTACKS When http:// is allowed or weakly filtered: Redis Gopher SSRF (full RCE potential) 6. BLIND SSRF DETECTION When response doesn't reflect fetched content: 1. Burp Collaborator / interact.sh : check for DNS + HTTP request from server 2. Pingback/webhook abuse : configure application's own webhook to your URL 3. Timing analysis : Internal open port vs closed port response time difference 4. Error analysis : Different error messages for "host not found" vs "connection refused" vs "timeout" reveal internal network topology 7. INTERNAL SERVICE EXPLOITATION Docker API (2375 unauthenticated) Elasticsearch (9200 no auth default) Redis (6379 — no auth common) Internal Admin Panels 8. SSRF + FILTER BYPASS DECISION TREE 9. THE SSRF FILTER MINDSET From zseano's methodology: if developers filter only 169.254.169.254 directly but not http://169.254.169.254/latest/meta data (full path), or forget about: IPv6 equivalents DNS names that resolve to internal IPs Redirect chains (server follows 302 to internal IP) Classic gap : App filters 127.0.0.1 but not 127.1 or [::1] or localhost . Application layer SSRF via XML (when app parses XML):

ssrf-server-side-request-forgery