pytm vs ThreatTree

pytm is a free, open-source Python framework for creating threat models from architectural descriptions. A model is defined in Python with elements such as servers, data stores, actors, processes, data flows, and trust boundaries. From it, pytm can generate data flow diagrams, sequence diagrams, and relevant threats. Templates can produce reports with diagrams and findings, and a RevealMD template can create slides for browser presentation. Data flow diagrams use Graphviz DOT, while sequence diagrams use PlantUML. Models can be imported from JSON with pytm's Python load function. Users can supply a custom threats file and change finding attributes such as CVSS score, response text, and severity. Requirements include Python 3.11 or later, Graphviz, Java OpenJDK 10 or 11, and plantuml.jar; Linux and macOS are listed, while Windows use is documented through Devbox in WSL. The project also documents container and Devbox dependency workflows. The README warns that strings in threats.json are evaluated with eval(), so the file's permissions need protection against unauthorized changes.

ThreatTree is a browser-based tool for organizing threat models into forests of Data Flow Diagrams and Attack Trees. It scores risks by likelihood and impact, then generates a ranked risk register across the trees in a forest. Threats can be tagged with STRIDE, LINDDUN, OWASP Top 10, CAPEC, and MITRE ATT&CK; mitigations can be mapped to standards including ISO 27001:2022, NIST SP 800-53 Rev 5, CIS Controls v8, PCI DSS v4.0, NIST CSF 2.0, and SOC 2. Teams can invite members with owner, editor, or viewer roles. Reports are available as PDFs, with JSON and STIX 2.1 exports. Optional per-forest AES-256-GCM encryption is available on every plan, including Free. ThreatTree says data is stored on UK servers, connections use TLS 1.2 or higher, and encrypted database backups are taken daily and retained for 30 days. The Free plan costs nothing and has limits on forests and trees. Pro costs $29 a month per user, billed monthly; Enterprise pricing is by quote.