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Basic Usage

For a detailed overview of AlterX options, visit the Usage page.
If you have questions, feel free to reach out through our Help page.

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Why AlterX?

What differentiates alterx from other subdomain permutation tools like goaltdns is its scripting feature. AlterX accepts patterns as input and generates subdomain permutation wordlists based on these patterns—similar to how Nuclei works with fuzzing-templates. Active Subdomain Enumeration is challenging due to the probability of finding actual existing domains. On a scale, this process can be visualized as: 
   Using Wordlist < generate permutations with subdomains (goaltdns) < alterx
Most subdomain permutation tools rely on hardcoded patterns, generating massive wordlists that may contain millions of subdomains—making bruteforcing with tools like dnsx infeasible. With alterx, you can create patterns based on results from passive subdomain enumeration, significantly increasing the chances of finding valid subdomains and making brute-forcing more efficient.

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Variables

alterx uses variable-like syntax similar to nuclei-templates. You can create custom patterns using these variables . when domains are passed as input alterx evaluates input and extracts variables from it .

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Basic Variables

{{sub}}     :  subdomain prefix or left most part of a subdomain
{{suffix}}  :  everything except {{sub}} in subdomain name is suffix
{{tld}}     :  top level domain name (ex com,uk,in etc)
{{etld}}    :  also know as public suffix (ex co.uk , gov.in etc)
Variableapi.scanme.shadmin.dev.scanme.shcloud.scanme.co.uk
{{sub}}apiadmincloud
{{suffix}}scanme.shdev.scanme.shscanme.co.uk
{{tld}}shshuk
{{etld}}--co.uk

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Advanced Variables

{{root}}  :  also known as eTLD+1 i.e only root domain (ex for api.scanme.sh => {{root}} is scanme.sh)
{{subN}}  :  here N is an integer (ex {{sub1}} , {{sub2}} etc) .

// {{subN}} is advanced variable which exists depending on input
// lets say there is a multi level domain cloud.nuclei.scanme.sh
// in this case {{sub}} = cloud and {{sub1}} = nuclei`
Variableapi.scanme.shadmin.dev.scanme.shcloud.scanme.co.uk
{{root}}scanme.shscanme.shscanme.co.uk
{{sub1}}-dev-
{{sub2}}---

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Patterns

In simple terms, a pattern is a template that describes what type of permutations AlterX should generate. 
// Below are some of example patterns which can be used to generate permutations
// assuming api.scanme.sh was given as input and variable {{word}} was given as input with only one value prod
// alterx generates subdomains for below patterns

"{{sub}}-{{word}}.{{suffix}}" // ex: api-prod.scanme.sh
"{{word}}-{{sub}}.{{suffix}}" // ex: prod-api.scanme.sh
"{{word}}.{{sub}}.{{suffix}}" // ex: prod.api.scanme.sh
"{{sub}}.{{word}}.{{suffix}}" // ex: api.prod.scanme.sh
You can find an example of a pattern configuration file here. This file is customizable based on your security assessments or penetration test requirements. This configuration file generates subdomain permutations for security assessments or penetration tests using customizable patterns and dynamic payloads. Patterns include dash-based, dot-based, and others. Users can create custom payload sections, such as words, region identifiers, or numbers, to suit their specific needs. For example, a user could define a new payload section env with values like prod and dev, then use it in patterns like {{env}}-{{word}}.{{suffix}} to generate subdomains like prod-app.example.com and dev-api.example.com. This flexibility allows tailored subdomain list for unique testing scenarios and target environments. Default pattern config file used for generation is stored in $HOME/.config/alterx/ directory, and custom config file can be also used using -ac option.

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Examples

An example of running alterx on existing list of passive subdomains of tesla.com yield us 10 additional NEW and valid subdomains resolved using dnsx. 
$ chaos -d tesla.com | alterx | dnsx

 

   ___   ____          _  __
  / _ | / / /____ ____| |/_/
 / __ |/ / __/ -_) __/>  <  
/_/ |_/_/\__/\__/_/ /_/|_|              

      projectdiscovery.io

[INF] Generated 8312 permutations in 0.0740s
auth-global-stage.tesla.com
auth-stage.tesla.com
digitalassets-stage.tesla.com
errlog-stage.tesla.com
kronos-dev.tesla.com
mfa-stage.tesla.com
paymentrecon-stage.tesla.com
sso-dev.tesla.com
shop-stage.tesla.com
www-uat-dev.tesla.com
Similarly -enrich option can be used to populate known subdomains as world input to generate target aware permutations. 
$ chaos -d tesla.com | alterx -enrich

   ___   ____          _  __
  / _ | / / /____ ____| |/_/
 / __ |/ / __/ -_) __/>  <  
/_/ |_/_/\__/\__/_/ /_/|_|              

      projectdiscovery.io

[INF] Generated 662010 permutations in 3.9989s
You can alter the default patterns at run time using -pattern CLI option. 
$ chaos -d tesla.com | alterx -enrich -p '{{word}}-{{suffix}}'

   ___   ____          _  __
  / _ | / / /____ ____| |/_/
 / __ |/ / __/ -_) __/>  <  
/_/ |_/_/\__/\__/_/ /_/|_|              

      projectdiscovery.io

[INF] Generated 21523 permutations in 0.7984s
You can also overwrite existing variable values using the -payload CLI options. 
$ alterx -list tesla.txt -enrich -p '{{word}}-{{year}}.{{suffix}}' -pp word=keywords.txt -pp year=2023

   ___   ____          _  __
  / _ | / / /____ ____| |/_/
 / __ |/ / __/ -_) __/>  <  
/_/ |_/_/\__/\__/_/ /_/|_|              

      projectdiscovery.io

[INF] Generated 21419 permutations in 1.1699s
For more information, check out the release blog
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