justm0rph3u5 / linkfinder

A python script that finds endpoints in JavaScript files

About LinkFinder

LinkFinder is a python script written to discover endpoints and their parameters in JavaScript files. This way penetration testers and bug hunters are able to gather new, hidden endpoints on the websites they are testing. Resulting in new testing ground, possibility containing new vulnerabilities. It does so by using jsbeautifier for python in combination with a fairly large regular expression. The regular expressions consists of four small regular expressions. These are responsible for finding:

• Full URLs (https://example.com/*)
• Absolute URLs or dotted URLs (/* or ../*)
• Relative URLs with atleast one slash (text/test.php)
• Relative URLs without a slash (test.php)

The output is given in HTML. Karel_origin has written a chrome extension for LinkFinder which can be found here.

Screenshots

Installation

LinkFinder supports Python 2 & 3.

$ git clone https://github.com/GerbenJavado/LinkFinder.git
$ cd LinkFinder
$ python setup.py install

Dependencies

LinkFinder depends on the argparse and jsbeautifier python modules. These dependencies can all be installed using pip.

Usage

Short Form	Long Form	Description
-i	--input	Input a: URL, file or folder. For folders a wildcard can be used (e.g. '/*.js').
-o	--output	Where to save the file, including file name or output to CLI. Default: output.html
-r	--regex	RegEx for filtering purposes against found endpoints (e.g. ^/api/)
-d	--domain	Toggle to use when analyzing an entire domain. Enumerates over all found JS files.
-b	--burp	Toggle to use when inputting a Burp 'Save selected' file containing multiple JS files
-c	--cookies	Add cookies to the request
-h	--help	show the help message and exit

Examples

• Most basic usage to find endpoints in an online JavaScript file and output the results to results.html:

python linkfinder.py -i https://example.com/1.js -o results.html

• CLI ouput (doesn't use jsbeautifier, which makes it very fast):

python linkfinder.py -i https://example.com/1.js -o cli

• Analyzing an entire domain and its JS files:

python linkfinder.py -i https://example.com -d

• Burp input (select in target the files you want to save, right click, Save selected items, feed that file as input):

python linkfinder.py -i burpfile -b

• Enumerating an entire folder for JavaScript files, while looking for endpoints starting with /api/ and finally saving the results to results.html:

python linkfinder.py -i 'Desktop/*.js' -r ^/api/ -o results.html

Unit-test

• Require pytest

pytest test_parser.py

Final remarks

• This is the first time I publicly release a tool. Contributions are much appreciated!
• LinkFinder is published under the MIT License.
• Thanks to @jackhcable for providing me with feedback.
• Special thanks @edoverflow for making this project a lot cleaner and awesome.