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                                    Author: Yassine Aboukir
                                        Version: 1.4.7

What's this about?

Sublert is a security and reconnaissance tool that was written in Python to leverage certificate transparency for the sole purpose of monitoring new subdomains deployed by specific organizations and issued TLS/SSL certificate. The tool is supposed to be scheduled to run periodically at fixed times, dates, or intervals (Ideally each day). New identified subdomains will be sent to Slack workspace with a notification push. Furthermore, the tool performs DNS resolution to determine working subdomains.


  • Virtual Private Server (VPS) running on Unix. (I personally use digitalOcean)
  • Python 2.x or 3.x.
  • Free Slack workspace.

Installation & Configuration

Please refer to below article for a detailed technical explanation:


Short Form Long Form Description
-u --url Adds a domain to monitor. E.g:
-d --delete Domain to remove from the monitored list. E.g:
-a --list Listing all monitored domains.
-t --threads Number of concurrent threads to use (Default: 20).
-r --resolve Perform DNS resolution.
-l --logging Enable Slack-based error logging.
-m --reset Reset everything.
-q --question "yes" or "no" to enable/disable questions asking for input.

Feedback and issues?

If you have any feedback, anything that you want to see implemented or running into issues using Sublert, please feel free to file an issue on


If you appreciate my work and wish to support it, feel free to:

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