Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

Second Order

Scans web applications for second-order subdomain takeover by crawling the app, and collecting URLs (and other data) that match certain rules, or respond in a certain way.


From binary

Download a prebuilt binary from the releases page and unzip it.

From source

Go version 1.17 is recommended.

go install -v


docker pull mhmdiaa/second-order

Command line options

  -target string
        Target URL
  -config string
        Configuration file (default "config.json")
  -depth int
        Depth to crawl (default 1)
  -header value
    	Header name and value separated by a colon 'Name: Value' (can be used more than once)
        Accept untrusted SSL/TLS certificates
  -output string
        Directory to save results in (default "output")
  -threads int
        Number of threads (default 10)

Configuration File

Example configuration files are in config

  • LogQueries: A map of tag-attribute queries that will be searched for in crawled pages. For example, "a": "href" means log every href attribute of every a tag.
  • LogNon200Queries: A map of tag-attribute queries that will be searched for in crawled pages, and logged only if they contain a valid URL that doesn't return a 200 status code.
  • LogInline: A list of tags whose inline content (between the opening and closing tags) will be logged, like title and script


All results are saved in JSON files that specify what and where data was found

  • The results of LogQueries are saved in attributes.json
    "": {
        "input[name]": [
  • The results of LogNon200Queries are saved in non-200-url-attributes.json
    "": {
        "script[src]": [
  • The results of LogInline are saved in inline.json
    "": {
        "title": [
            "Example - Home"
      "": {
        "title": [
            "Example - login"

Usage Ideas

This is a list of tips and ideas (not necessarily related to second-order subdomain takeover) on what to use Second Order for.

  • Check for second-order subdomain takeover: takeover.json. (Duh!)
  • Collect inline and imported JS code: javascript.json.
  • Find where a target hosts static files cdn.json. (S3 buckets, anyone?)
  • Collect <input> names to build a tailored parameter bruteforcing wordlist: parameters.json.
  • Feel free to contribute more ideas!