Log4JHunt

An automated, reliable scanner for the Log4Shell CVE-2021-44228 vulnerability.

Video demo:

Usage

Here the help usage:

$ python3 log4jhunt.py

          +--------------+
              Log4JHunt
          +--------------+

[+] Log4jHunt by RedHunt Labs - A Modern Attack Surface (ASM) Management Company
[+] Author: Pinaki Mondal (RHL Research Team)
[+] Continuously Track Your Attack Surface using https://redhuntlabs.com/nvadr.

[-] You have to supply at least a single host to scan!

usage: log4jhunt.py [-h] [-u URL] [-f FILE] [-d DELAY] [-t TIMEOUT] [-T TOKEN] [-E EMAIL] [-W WEBHOOK] [-S SERVER] [-ua USERAGENT] [-m METHOD] [-H HEADERS] [-p PROXY]

optional arguments:
  -h, --help            show this help message and exit
  -u URL, --url URL     URL to probe for the vulnerability.
  -f FILE, --file FILE  Specify a file containing list of hosts to scan.
  -d DELAY, --delay DELAY
                        Delay in-between two concurrent requests.
  -t TIMEOUT, --timeout TIMEOUT
                        Scan timeout for a single host.
  -T TOKEN, --token TOKEN
                        Canary token to use in payloads for scanning.
  -E EMAIL, --email EMAIL
                        Email to receive notifications.
  -W WEBHOOK, --webhook WEBHOOK
                        Webhook URL to receive notifications.
  -S SERVER, --server SERVER
                        Custom DNS callback server for receiving notifications.
  -ua USERAGENT, --user-agent USERAGENT
                        Custom user agent string to use for requests.
  -m METHOD, --methods METHOD
                        Comma separated list of HTTP Method to use
  -H HEADERS, --headers HEADERS
                        Comma separated list of custom HTTP headers to use.
  -p PROXY, --proxy PROXY
                        HTTP proxy to use (if any).

Getting a token

The tool makes use of Log4Shell tokens from Canary Tokens. The tool has capability to automatically generate tokens, if the values of the token (--token) and server (--server) are empty.

Once the token is generated, the token and the auth value are written to a file called canary-token.json.

Targets specification

You can specify the targets in two modes:

• Scan a single URL:

  ./log4jhunt.py -u 1.2.3.4:8080 ...
  

• Use a file to specify a list of targets:

  ./log4jhunt.py -f targets.txt ...
  

Specifying notification channels

There are two ways in which you can receive notification channels:

• email (--email) -- service provided by Canarytokens.
• webhook (--webhook) -- service provided by Canarytokens.
• custom server (--server) -- you own custom DNS callback server.

Once the tool finds a vulnerable server, notifications would be relayed back to your preferred communication channel.

Sending requests

• You can customize the HTTP methods using --methods.
• A custom set of HTTP headers can be specified via --headers respectively.
• A custom user agent can be specified using --user-agent header.
• You can specfy a custom timeout value using --timeout.
• You can specify custom proxies to use in HTTP requests via --proxy.

Specifying delay

Since a lot of HTTP requests are involved, it might be a cumbersome job for the remote host to handle the requests. The --delay parameter is here to help you with those cases. You can specify a delay value in seconds -- which will be used be used in between two subsequent requests to the same port on a server.

More details around the Log4J

We have covered more details around Log4j Vulnerability in our Blog.

License & Version

The tool is licensed under the MIT license. See LICENSE.

Currently the tool is at v0.1.

Credits

The Research Team at RedHunt Labs would like to thank Thinkst Canary for the awesome Canary Token Project.

To know more about our Attack Surface Management platform, check out NVADR.