aeondave/malskill/massdns

Name: massdns
Author: aeondave

Claude Code and agent skill by aeondave/malskill

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Auth/lab ref: High-performance DNS resolver for bulk subdomain resolution. For you have a large subdomain list and need to resolve all entries quickly using public resolvers.

Install

npx vskill@latest install aeondave/malskill/massdns

SKILL.md

MassDNS

High-speed DNS bulk resolver — resolve millions of subdomains per minute.

Quick Start

bash

git clone https://github.com/blechschmidt/massdns
cd massdns && make
 
# Resolve subdomain list
./bin/massdns -r resolvers.txt -t A subdomains.txt -o S -w resolved.txt
 
# Built-in resolver list
./bin/massdns -r lists/resolvers.txt -t A subdomains.txt -o S > resolved.txt

Core Flags

Flag	Purpose
`-r FILE`	Resolver list file
`-t TYPE`	DNS type (A/AAAA/MX/NS/CNAME)
`-o FORMAT`	Output format (S=simple, J=JSON, L=list)
`-w FILE`	Write output to file
`-s N`	Concurrent lookups (default: 10000)
`--root`	Do not drop privileges when running as root (not recommended)
`--verify-ip`	Verify source IP addresses of incoming replies
`--flush`	Flush output file after each response
`-q`	Quiet mode
`--status-format <fmt>`	Status line format
`--retry`	Specify unacceptable DNS response codes to retry

Output Formats

Flag	Format	Example Output
`-o S`	Simple (default)	`sub.target.com. A 1.2.3.4`
`-o J`	JSON	Full DNS response JSON
`-o L`	List	`sub.target.com` (only names)
`-o F`	Full	All DNS fields

Common Workflows

Subdomain enumeration pipeline:

bash

# Generate candidates with subfinder
subfinder -d target.com -silent -o subs.txt
 
# Resolve with massdns
./bin/massdns -r lists/resolvers.txt -t A subs.txt -o S | grep -v NXDOMAIN > live.txt

Extract live IPs:

bash

cat resolved.txt | grep " A " | awk '{print $3}' | sort -u > ips.txt

DNS brute-force (generate + resolve):

bash

# Generate permutations with puredns or subfinder, then resolve at scale
subfinder -d target.com -silent -all | \
  massdns -r lists/resolvers.txt -t A -o S 2>/dev/null | \
  grep -v "NXDOMAIN\|SERVFAIL" > resolved.txt

CNAME hunting for subdomain takeover:

bash

massdns -r lists/resolvers.txt -t CNAME subs.txt -o J 2>/dev/null | \
  jq -r 'select(.answers[0].type=="CNAME") | "\(.name) \(.answers[0].data)"' | \
  grep -v "target\.com"

MX record enumeration:

bash

massdns -r lists/resolvers.txt -t MX domains.txt -o S 2>/dev/null | \
  grep " MX " | sort -u

-s limits concurrent lookups, not requests per second. Choose resolvers and concurrency appropriate for the authorized workload.

Resources

File	When to load
`references/resolvers.md`	Resolver list sources, rate tuning, wildcard handling, puredns integration

Security

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Source

SKILL.md in the repositoryCheckingoffensive-tools/recon/massdns/SKILL.md

Popularity

Repository stars: 22
Repository forks: 2
7-day trend score: 21

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