Fast & user-friendly subdomain monitoring tool for continous attack surface management.

Why opt for sub.Monitor? This program offers easy setup due to its utilization of SQLite for storing all identified domains (removing the necessity for prior database management). Moreover, it boasts high customizability, with users needing to append only a few lines of code to the script using their chosen tools. In contrast to other existing solutions relying on databases such as MySQL or MongoDB, initializing the script can turn into a tedious task.

• Fast
• Easy to use
• Easy to install
• Easy to customize
• Continuously save subdomains in the local database (with the possibility of dumping them all)
• Telegram/slack/discord notifications

sub.Monitor flags:

options:
  --add ADD    Domain to scan
  --file FILE  File with known subdomains
  -d D         Domain to scan
  -h A         Hours between scans
  --dump       Dump all subdomains for a specific domain
  --list       List all root domains in the database
  -help, -?    Show this help message and exit

You need to write the configuration (api) path files into config.ini file.

• Subfinder api configuration file.
• Amass api configuration file.
• Notify api configuration file.
• You will need to specify the binary and config paths on sub.monitor-config.ini file.
• Finally, execute pip3 install -r requirements.txt

You can easily implement your own tools on the script, just modify the lines of code:

def run_tool(tool, domain, output_file):
    print(f'[{datetime.datetime.now()}] - Running {tool} on {domain}')
    if tool == 'assetfinder':
        assetfinder_binary = config.get('Binary paths', 'assetfinder')
        cmd = f'echo {domain} | {assetfinder_binary} -subs-only | grep -E "{domain}$" |grep -v "*" | grep -v "@"'
    elif tool == 'subfinder':
        subfinder_binary = config.get('Binary paths', 'subfinder')
        subfinder_api = config.get('Api', 'subfinder_api')
        cmd = f'{subfinder_binary} -d {domain} -silent -pc {subfinder_api} -all'
    elif tool == 'amass':
        amass_binary = config.get('Binary paths', 'amass')
        amass_api = config.get('Api', 'amass_api')
        cmd = f'{amass_binary} enum -passive -norecursive -noalts -d {domain} -config {amass_api}'
    elif tool == 'my-custom-tool':
        my-custom-tool-binary = config.get('Binary paths', 'my-custom-tool-binary-or-script')
        cmd = f'{my-custom-tool-binary} -d {domain}'

Also add your tool name here:

                for tool in ['subfinder', 'amass', 'assetfinder', 'my-custom-tool-name']:
                    run_tool(tool, domain, output_file)

Finally, of course, you need to add the tool on the sub.monitor-config.ini file so that the python script can get the binary from that configuration file.

The only needed thing is that once the command is finished, it must show on the output all the domains discovered so the tool can save them on the logs file and inside the database

First of all sub.Monitor needs a list of already scanned domains:

➜  cat ibm_sorted_subdomains.txt
test1.ibm.com
test2.ibm.com
test3.ibm.com
subtest.testX.ibm.com
...

Now, the file containing the subdomains can be passed to sub.Monitor with the following command:

python3 monitor.py --add ibm.com --file ibm_sorted_subdomains.txt
          _    ___  ___            _ _
          | |   |  \/  |           (_) |
 ___ _   _| |__ | .  . | ___  _ __  _| |_ ___  _ __
/ __| | | | '_ \| |\/| |/ _ \| '_ \| | __/ _ \| '__|
\__ \ |_| | |_) | |  | | (_) | | | | | || (_) | |
|___/\__,_|_.__/\_|  |_/\___/|_| |_|_|\__\___/|_|

                    github.com/e1abrador/sub.Monitor

[2023-06-06 18:16:26.002521] - 538 subdomains were added to the local database.

To confirm that the domain has been added to the database, execute:

python3 monitor.py --list
          _    ___  ___            _ _
          | |   |  \/  |           (_) |
 ___ _   _| |__ | .  . | ___  _ __  _| |_ ___  _ __
/ __| | | | '_ \| |\/| |/ _ \| '_ \| | __/ _ \| '__|
\__ \ |_| | |_) | |  | | (_) | | | | | || (_) | |
|___/\__,_|_.__/\_|  |_/\___/|_| |_|_|\__\___/|_|

                    github.com/e1abrador/sub.Monitor

ibm.com [9 subdomains added manually] [2 subdomains discovered] [11 total unique in database]

Once it has been correctly loaded, the monitoring process can start. It is recommended to use TMUX in a VPS and leave it running for a long time. With the following command, the script will be running the subdomain enumeration tools and will compare the new results with the old results. If there's any new subdomain found, sub.Monitor will first add it to the local database (so it will not notify anymore about that discovery) and then will notify the user via slack/telegram/discord.

python3 monitor.py -d ibm.com -h 8

If any subdomain is found, sub.Monitor will show the following message on the output:

➜ python3 monitor.py -d ibm.com -h 12

          _    ___  ___            _ _
          | |   |  \/  |           (_) |
 ___ _   _| |__ | .  . | ___  _ __  _| |_ ___  _ __
/ __| | | | '_ \| |\/| |/ _ \| '_ \| | __/ _ \| '__|
\__ \ |_| | |_) | |  | | (_) | | | | | || (_) | |
|___/\__,_|_.__/\_|  |_/\___/|_| |_|_|\__\___/|_|

                    github.com/e1abrador/sub.Monitor

[2023-06-06 18:07:25.191169] - New subdomain xxxx.ibm.com discovered
[2023-06-06 18:07:25.353156] - New subdomain xyxyxyxyxyx.ibm.com discovered
[2023-06-06 18:07:25.641082] - New subdomain x1.xxxx.ibm.com discovered

It is also possible to monitor more than 1 domain, with the following command:

python3 monitor.py -df root-domains.txt -h 8

After those messages are reported, on the same time the user will receive the notifications on telegram

How do I manage the notifications? I found a pretty easy (and easy to manage) way to see all newly discovered domains with Discord. I got this (blurred since all of them are private programs):

The idea is first to create a category regarding the program name:

> Yahoo

--- yahoo.com

--- yahoo.net

--- etc ...

> IBM

--- ibm.com

--- whateverdomain.com

--- etc ...

This is what my notify config file looks like:

I recommend doing this for each domain (it may be pretty tedious to set up this but it is a great way to manage the results). monitor.py script will send the results to the given webhook based on the ID (which must be the same as the domain name to scan).

Let's say that the script has been running for 2 months and you want to get all the results (old subdomains and newly discovered ones). With sub.Monitor whether it is possible using the --dump flag:

python3 monitor.py -d ibm.com --dump

          _    ___  ___            _ _
          | |   |  \/  |           (_) |
 ___ _   _| |__ | .  . | ___  _ __  _| |_ ___  _ __
/ __| | | | '_ \| |\/| |/ _ \| '_ \| | __/ _ \| '__|
\__ \ |_| | |_) | |  | | (_) | | | | | || (_) | |
|___/\__,_|_.__/\_|  |_/\___/|_| |_|_|\__\___/|_|

                    github.com/e1abrador/sub.Monitor

Subdomains for ibm.com:
subdomain1.ibm.com
subdomain2.ibm.com
...

You can also use the following command to see the day on which the domain was discovered:

python3 monitor.py -d ibm.com --dump --info

          _    ___  ___            _ _
          | |   |  \/  |           (_) |
 ___ _   _| |__ | .  . | ___  _ __  _| |_ ___  _ __
/ __| | | | '_ \| |\/| |/ _ \| '_ \| | __/ _ \| '__|
\__ \ |_| | |_) | |  | | (_) | | | | | || (_) | |
|___/\__,_|_.__/\_|  |_/\___/|_| |_|_|\__\___/|_|

                    github.com/e1abrador/sub.Monitor

Subdomains for ibm.com:
test.ibm.com [discovered on 06/08/2023]
test2.ibm.com [discovered on 08/08/2023]

Thanks to:

• Projectdiscovery for creating subfinder and notify!.
• Thanks to OWASP for their amazing project amass!.
• Tomnomnom for creating assetfinder!.

• Implement the monitoring of more than 1 subdomain. [DONE]
• Continuously read the domain files so new domains can be scanned without stopping the program. [DONE]
• Implement out of scope filtering [Soon]

If you have any idea of some new functionality open a PR at https://github.com/e1abrador/sub.Monitor/pulls.

Good luck and good hunting! If you really love the tool (or any others), or they helped you find an awesome bounty, consider BUYING ME A COFFEE! ☕ (I could use the caffeine!)

⚪ e1abrador

Twitter: https://twitter.com/C4yyyy