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Thick Client Testing

Desktop app testing for local logic, protocols, and trust

We assess binaries, update paths, storage, and backend trust to see how a local foothold could drive bigger impact.

What teams usually value in this service

Binary and protocol-level review
Client-to-server trust validation
Remediation guidance for desktop teams

What is covered

  • Local storage, secrets, and offline trust decisions
  • Custom protocols, serialization, and client-server message handling
  • Update paths, patch behavior, and integrity assumptions
  • Privilege assumptions in local workflows and executable logic
  • How backend systems trust signals coming from the client

Who this service is for

  • Teams shipping desktop apps with sensitive workflows
  • Orgs relying on thick clients for internal systems
  • Products where local logic could affect central systems

Common attack paths and issues tested

Local logic abuse

We test whether critical decisions are made in the client where they can be bypassed, modified, or replayed.

Protocol tampering and unsafe serialization

Custom transport and message formats are assessed for trust gaps, injection, and unsafe deserialization behaviors.

Update and integrity path weakness

We review how the application updates, validates packages, and protects against tampered or downgraded binaries.

What clients receive

  • Findings mapped to client behavior, backend trust, and operational impact
  • Clear guidance for desktop engineering and platform teams
  • Evidence that supports remediation tracking and customer review if needed
  • Retest support after fixes

Engagement process

  1. 1Define client workflows, backend dependencies, and threat priorities
  2. 2Assess the binary, local behavior, and communication patterns
  3. 3Validate exploitability and realistic impact paths
  4. 4Provide reporting, walkthrough, and retesting

Related resources

Articles that help teams evaluate and prepare for this service

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Frequently asked questions

Is thick client testing different from web app testing?

Yes. Local execution, protocol handling, and update mechanisms create risks that are not visible in a browser-based assessment.

Do you need source code?

Not necessarily. A build, installer, and test environment are often enough to perform an effective black-box or gray-box review.