Proposing new type (kval) support for extractors

[ehsandeep]

As of now, only regex type extractors are supported, as discussed previously we can start with adding new type of support which allows to pull key:value formatted data from response header and cookie and later extend this type or add another one to pull data from response body based on tags/elements/id, etc.

Here is an example template that will extract value from the response header for the given header key.

id: extractors-example

info:
  name: Extractors Test
  author: pdteam
  severity: info

requests:
  - method: GET
    path:
      - "{{BaseURL}}/"
      
    extractors:
      - type: kval
        name: server
        kval:
          - "server"

> echo https://www.hackerone.com | nuclei -t extractors-example.yaml -silent 

[extractors-example] [http] http://example.com [cloudflare]

Where raw response looks like this, this applies to cookies as well, they are also stored in key:value format.

age: 119
via: varnish
x-cache: HIT
x-cache-hits: 9
cf-cache-status: DYNAMIC
cf-request-id: 03e880ebba0000e291c1a68200000001
server: cloudflare
cf-ray: 5b210425ffcde291-NAG

[ehsandeep]

This type kval will support two types of input and limited to headers for now, as it primarily aims to get data from headers and cookies, examples are as follows.

key:value
key=value