🌀 Shortscan

An IIS short filename enumeration tool.

Functionality

Shortscan is designed to quickly determine which files with short filenames exist on an IIS webserver. Once a short filename has been identified the tool will try to automatically identify the full filename.

In addition to standard discovery methods Shortscan also uses a unique checksum matching approach to attempt to find the long filename where the short filename is based on Windows' propriatary shortname collision avoidance checksum algorithm (more on this research at a later date).

Installation

Quick install

Using a recent version of go:

go install github.com/thezakman/shortscan/cmd/shortscan@latest

Manual install

To build (and optionally install) locally:

go get && go build
go install

Usage

Basic usage

Shortscan is easy to use with minimal configuration. Basic usage looks like:

$ shortscan http://example.org/

Examples

This example sets multiple custom headers by using --header/-H multiple times:

shortscan -H 'Host: gibson' -H 'Authorization: Basic ZGFkZTpsMzN0'

To check whether a site is vulnerable without performing file enumeration use:

shortscan --isvuln

To test for Source Code Disclosure in ASP.NET ::$INDEX_ALLOCATION and :$i30:$INDEX_ALLOCATION vulnerabilities:

shortscan http://www.example.org/bin -i -w ~/wordlists/rainbow/dll.rainbow --fullurl --autocomplete method

Advanced features

The following options allow further tweaks:

Shortscan v0.9.4 · an IIS short filename enumeration tool by bitquark & TheZakMan
Usage: shortscan [--wordlist FILE] [--header HEADER] [--concurrency CONCURRENCY] [--timeout SECONDS] [--output type] [--verbosity VERBOSITY] [--fullurl] [--stabilise] [--patience LEVEL] [--characters CHARACTERS] [--autocomplete mode] [--isvuln] URL

Positional arguments:
  URL                    url to scan

Options:
  --list FILE, -l FILE   file containing list of URLs to scan
  --wordlist FILE, -w FILE
                         combined wordlist + rainbow table generated with shortutil
  --header HEADER, -H HEADER
                         header to send with each request (use multiple times for multiple headers)
  --concurrency CONCURRENCY, -c CONCURRENCY
                         number of requests to make at once [default: 20]
  --timeout SECONDS, -t SECONDS
                         per-request timeout in seconds [default: 10]
  --output format, -o format
                         output format (human = human readable; json = JSON) [default: human]
  --verbosity VERBOSITY, -v VERBOSITY
                         how much noise to make (0 = quiet; 1 = debug; 2 = trace) [default: 0]
  --fullurl, -F          display the full URL for confirmed files rather than just the filename [default: false]
  --norecurse, -n        don't detect and recurse into subdirectories (disabled when autocomplete is disabled) [default: false]
  --stabilise, -s        attempt to get coherent autocomplete results from an unstable server (generates more requests) [default: false]
  --patience LEVEL, -p LEVEL
                         patience level when determining vulnerability (0 = patient; 1 = very patient) [default: 0]
  --characters CHARACTERS, -C CHARACTERS
                         filename characters to enumerate [default: JFKGOTMYVHSPCANDXLRWEBQUIZ8549176320-_()&'!#$%@^{}~]
  --autocomplete mode, -a mode
                         autocomplete detection mode (auto = autoselect; method = HTTP method magic; status = HTTP status; distance = Levenshtein distance; none = disable) [default: auto]
  --isvuln, -V           bail after determining whether the service is vulnerable [default: false]
  --index, -i            test ::$INDEX_ALLOCATION and :$i30:$INDEX_ALLOCATION
  --backwards-recurse, -r
                         perform regressive scanning on parent directories [default: false]
  --help, -h             display this help and exit
  --version              display version and exit

Utility

The shortscan project includes a utility named shortutil which can be used to perform various short filename operations and to make custom rainbow tables for use with the tool.

Examples

You can create a rainbow table from an existing wordlist like this:

shortutil wordlist input.txt > output.rainbow

To generate a one-off checksum for a file:

shortutil checksum index.html

Usage

Run shortutil <command> --help for a definiteive list of options for each command.

Shortutil v0.9.4 · a short filename utility by bitquark & TheZakMan
Usage: main <command> [<args>]

Options:
  --help, -h             display this help and exit

Commands:
  wordlist               add hashes to a wordlist for use with, for example, shortscan
  checksum               generate a one-off checksum for the given filename

Wordlist

A custom wordlist was built for shortscan. For full details see pkg/shortscan/resources/README.md

Credit

Original IIS short filename research by Soroush Dalili.

Source Code Disclosure in ASP.NET research by Arseniy Sharoglazov.

Implementation of the -i feature by ke0ge.

Additional research and this project by bitquark.