certmitm

certmitm automatically tests for — and exploits — certificate validation vulnerabilities in the TLS connections made by a client device or application. Many IoT devices fail to properly validate server certificates, and certmitm turns that class of bug into an easy, repeatable check.

Good for:

• Testing whether an IoT device or app properly validates TLS certificates.
• Automatically intercepting connections from devices that accept bad certificates.
• Quickly surfacing MITM-able traffic during device assessments.

Notes: Created by Aapo Oksman (MIT License) and presented at DEF CON 31 (August 2023): "certmitm: automatic exploitation of TLS certificate validation vulnerabilities." Slides and a demo recording are available from the DEF CON media archive.