Senior Security / QA Lead - 12 Weeks (569)

**Senior Security / QA Lead **

Are you looking to advance in your international career? We are here to assist you!

Ubiminds is a people-centric company partnering with American software firms to expand their development capabilities. We specialize in sourcing the top 5% of Brazilian talent for their LATAM ventures, offering a tailored blend of staff augmentation and employer-of-record services.

Challenge

We are seeking an experienced Senior Security / QA Lead to spearhead adversarial security testing strategies. This role entails validating the platform against the freeze-audit self-test suite and designing and executing security coverage on top of it. The position requires expertise in security testing, technical proficiency, meticulous defect reporting, and working directly with real codebases.

The engagement is full-time, lasting approximately 12 weeks, and can be carried out remotely in LATAM.

Responsibilities

• Develop and oversee adversarial security testing of the determined decision path.
• Test scenarios like default-DENY breach attempts, privilege escalation, and tenant cross-boundary violations.
• Evaluate multi-tenant isolation and owner-customer segmentation utilizing the platform's roster subsystem.
• Validate the tamper-proof nature of the hash-chained audit trail, including append-only behavior and detection of tampering attempts.
• Verify tenant and operator role authentication and authorization.
• Enhance and review the existing per-module freeze-audit self-tests.
• Ensure every governance rule effectively translates through the live intake path.
• Prioritize findings by severity and provide clear replication steps using GitHub Issues.
• Maintain alignment with the freeze-audit CI gate.
• Enforce the merge gate requiring a green freeze-audit CI status.
• Collaborate with the client on approving any governance-core adjustments.

Mandatory Skills

• Profound background in security testing, encompassing penetration testing and authorization/access-control testing.
• Hands-on experience with Python and the ability to comprehend and create tests against codebases.
• Familiarity with multi-tenant SaaS environments and knowledge of tenant isolation failures.
• Practical understanding of cryptographic audit trails and tamper-evidence verification.
• Experience with Docker, CI workflows like GitHub Actions, and working with a green-CI merge gate.
• Proficiency in Postgres for validation purposes.
• Strong written English skills.
• Ability to produce detailed and replicable defect reports.

Nice to Have

• Past experience in testing policy engines, authorization systems, or agentic-AI guardrails.
• Exposure to SOC 2 controls and evidence requirements.
• Familiarity with Render or similar container hosting platforms.
• Previous work in regulated or safety-critical sectors.

Team & Environment

• Department: Nehemiah Layer.
• Specializing in security testing, adversarial coverage, and audit-chain integrity.
• Role Level: Senior / Lead.
• Reports to: Ubiminds Engagement Manager.
• Duration: 12-week full-time engagement, remote position in LATAM.
• Focus on security, governance, and platform integrity.
• Emphasis on reproducible testing, CI compliance, and architectural endorsement.

Success in the First 12 Weeks

• Implementation of a thorough adversarial test suite targeting default-DENY and tenant isolation.
• Independent confirmation of audit-chain tamper-evidence.
• Detailed report of severity-ranked findings aiding SOC 2 readiness and piloting.
• Maintain freeze-audit CI green status with a structured defect tracking process.

About Ubiminds

Our Culture

• People come first.
• We encourage continuous self-improvement.
• Emphasis on proactivity, ownership, and dedication.
• We champion teamwork and shared growth.
• Commitment to delivering exceptional services exceeding expectations.
• Honesty, transparency, and openness are our ethos.

Perks and Benefits

• Placement in a product-based company with full-team treatment.
• Back-office support including career guidance, HR, and personal assistance services.
• Remote-first policy.
• MacBook provided.
• Access to tech events, meetings, and a supportive community of top engineers.
• English improvement lessons with a native speaker.
• Referral bonuses for recommending new team members.
• Florianópolis HQ office available for office ambiance, offering snacks, massages, drinks, and games.