How Big Tech Interviews Security Engineers in 2026
A senior security engineer’s guide to how modern security roles are evaluated
Welcome to the newsletter, and thank you to the 900 new subscribers and 8 new paying members who’ve joined since the last issue. Your support genuinely means a lot.
Quick introduction for new readers: I’m Saed, a Senior Security Engineer at Google, based in London. I hold a Master’s degree in Software Engineering from the University of Westminster and have spent over 6 years in the industry.
I started my career as a physical security guard, transitioned into IT support, moved into cloud engineering, and eventually into security, giving me a practical, end-to-end view of how security actually works in real systems.
If you’re preparing for Security Engineering roles in 2026, this edition is intentionally dense and practical. I spent over 3 hours compiling and refining this list based on my experience as a Senior Security Engineer with 6+ years in the industry, and on how Big Tech actually evaluates security engineers today.
This is not a trivia list.
These are the questions used to evaluate judgment, tradeoff thinking, and real-world security maturity.
The 50 questions are grouped into 6 core categories. For each category, I’ve included:
- The intent behind the questions
- What interviewers are really testing
- What strong answers consistently demonstrate
Use this as a study guide, a self-assessment tool, or a framework to structure your own answers.
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A) Security Fundamentals & Core Concepts (1–10)
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1) What is the CIA Triad and how does it apply in real systems?
Focus: Foundational security thinking
Core Idea: Security is about tradeoffs, not absolutes
Strong Answers Cover:
• Risk-based prioritisation between availability vs confidentiality
• Business impact of breaches vs downtime
• Why availability failures often matter more than data loss
• Long-term trust implications
2) Authentication vs Authorisation. Explain with examples.
Focus: Identity clarity
Core Idea: Most security bugs are access bugs
Strong Answers Cover:
• Clear boundary between identity and permissions
• Real production failures caused by confusion
• How mistakes scale quietly
• Developer ergonomics vs safety
3) Explain XSS, CSRF, and SSRF.
Focus: Web security reasoning
Core Idea: Attacks exploit misplaced trust
Strong Answers Cover:
• Threat models, not definitions
• Where trust breaks in modern apps
• Prevention as design, not filters
• Developer education impact
4) What is SQL Injection and how is it prevented properly?
Focus: Secure coding fundamentals
Core Idea: Input handling is architecture, not validation
Strong Answers Cover:
• Parameterisation vs sanitisation
• ORM false sense of safety
• Risk reduction at framework level
• Long-term maintenance impact
5) What is a replay attack and how do you prevent it?
Focus: Protocol reasoning
Core Idea: Freshness matters as much as secrecy
Strong Answers Cover:
• Nonces, timestamps, token expiry
• Tradeoffs with distributed systems
• Failure modes under clock skew
• Operational risks
6) Hashing vs Encryption vs Encoding
Focus: Crypto fundamentals
Core Idea: Wrong primitive equals broken security
Strong Answers Cover:
• Use cases, not math
• Irreversibility vs confidentiality
• Compliance expectations
• Developer misuse patterns
7) Symmetric vs Asymmetric encryption
Focus: Practical crypto usage
Core Idea: Trust and performance tradeoffs
Strong Answers Cover:
• Key distribution challenges
• Hybrid models (TLS)
• Scalability concerns
• Real-world misuse
8) How does TLS work end to end?
Focus: Secure communication depth
Core Idea: Validation failures break everything
Strong Answers Cover:
• Cert chains and trust anchors
• MITM risks
• Misconfiguration risks
• Long-term platform trust
9) What is Least Privilege and how do you enforce it?
Focus: Access design
Core Idea: Permissions decay silently
Strong Answers Cover:
• Guardrails over reviews
• Automation vs manual enforcement
• Developer trust balance
• Long-term blast radius reduction
10) What is Defense in Depth?
Focus: Security architecture
Core Idea: Assume failure, not perfection
Strong Answers Cover:
• Layered controls
• Cost vs protection tradeoffs
• Failure containment
• Strategic resilience
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B) Cloud Security & Infrastructure (11–19)
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11) Common IAM misconfigurations you’ve seen
Focus: Real-world experience
Core Idea: Identity is the cloud perimeter
Strong Answers Cover:
• Over-permissioned roles
• Lateral movement risk
• Monitoring gaps
• Long-term permission creep
12) How do you design IAM for microservices?
Focus: Service identity
Core Idea: Humans shouldn’t be in the auth path
Strong Answers Cover:
• Service-to-service auth
• Short-lived credentials
• Operational complexity
• Scalability impact
13) How do you secure cloud networking?
Focus: Network isolation
Core Idea: Flat networks amplify damage
Strong Answers Cover:
• Segmentation strategies
• Zero trust assumptions
• Cost vs complexity
• Failure containment
14) Securing object storage like S3 or GCS
Focus: Data exposure prevention
Core Idea: Defaults are dangerous
Strong Answers Cover:
• Access policies
• Logging and alerting
• Public exposure risks
• Long-term data trust
15) Secrets management in cloud environments
Focus: Sensitive data handling
Core Idea: Secrets leak through convenience
Strong Answers Cover:
• Rotation strategies
• Developer UX
• Automation vs risk
• Incident response readiness
16) What is shared responsibility in cloud security?
Focus: Accountability clarity
Core Idea: Assumptions cause breaches
Strong Answers Cover:
• Provider vs customer boundaries
• Misplaced trust
• Audit readiness
• Long-term ownership clarity
17) Cloud logging strategy for security
Focus: Visibility
Core Idea: You cannot defend what you cannot see
Strong Answers Cover:
• Control plane vs data plane
• Cost tradeoffs
• Signal quality
• Detection maturity
18) How do you think about cloud threat modeling?
Focus: Attacker mindset
Core Idea: Assume breach
Strong Answers Cover:
• Identity abuse
• Lateral movement
• Persistence
• Recovery planning
19) Cloud security vs on-prem security differences
Focus: Mental model shift
Core Idea: Speed increases risk
Strong Answers Cover:
• Automation impact
• Shared tooling risk
• Control loss
• Long-term governance
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C) Application Security & Secure SDLC (20–28)
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20) How do you secure APIs in a modern microservices architecture?
Focus: AppSec design thinking
Core Idea: APIs are the most attacked surface today
Strong answers cover:
• AuthN vs AuthZ at the API layer
• Rate limiting, abuse detection, and input validation
• Tradeoffs between security and developer velocity
• Long-term API versioning and backward compatibility risks
21) What are the most common application security mistakes you see?
Focus: Pattern recognition
Core Idea: Most bugs repeat, only contexts change
Strong answers cover:
• Broken access control
• Secrets exposure
• Insecure defaults
• Why teams repeat the same mistakes at scale
22) How do you integrate security into CI/CD pipelines?
Focus: Shift-left maturity
Core Idea: Security that blocks pipelines gets bypassed
Strong answers cover:
• SAST vs DAST vs dependency scanning tradeoffs
• False positive management
• Developer trust and adoption
• Measuring effectiveness over time
23) How do you think about dependency and supply chain security?
Focus: Modern attack vectors
Core Idea: Your code is only as safe as your weakest dependency
Strong answers cover:
• SBOMs and dependency visibility
• Risk-based patching
• Balancing velocity with exposure
• Long-term ecosystem risk
24) How do you handle secrets in application code?
Focus: Secure engineering discipline
Core Idea: Secrets leak through convenience
Strong answers cover:
• Environment-based secret injection
• Rotation and revocation
• Developer ergonomics
• Incident response readiness
25) What is your approach to secure authentication flows?
Focus: Identity-first security
Core Idea: Auth bugs are catastrophic bugs
Strong answers cover:
• Token lifecycle management
• Session handling risks
• Tradeoffs between UX and security
• Long-term identity trust
26) How do you test security controls in applications?
Focus: Validation mindset
Core Idea: Controls that aren’t tested don’t exist
Strong answers cover:
• Automated vs manual testing
• Regression prevention
• Coverage gaps
• Metrics for confidence
27) How do you educate developers about security without slowing them down?
Focus: Influence and communication
Core Idea: Security scales through people, not policies
Strong answers cover:
• Just-in-time education
• Secure defaults
• Feedback loops
• Long-term culture building
28) How do you balance security requirements with product deadlines?
Focus: Judgment
Core Idea: Security is prioritisation, not absolutism
Strong answers cover:
• Risk acceptance vs mitigation
• Business alignment
• Documented tradeoffs
• Trust with leadership
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D) Threat Modeling & System Design (29–35)
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29) How do you approach threat modeling for a new system?
Focus: Structured thinking
Core Idea: Ask before answering
Strong answers cover:
• Assets, actors, trust boundaries
• Clarifying assumptions
• Threat prioritisation
• Long-term design impact
30) Threat model a real-world product (e.g., payment system)
Focus: Applied reasoning
Core Idea: Practical beats theoretical
Strong answers cover:
• Abuse cases
• Failure modes
• Defense tradeoffs
• Business risk alignment
31) How do you prioritise security risks?
Focus: Risk management
Core Idea: Not all risks deserve equal attention
Strong answers cover:
• Impact vs likelihood
• User trust implications
• Cost of mitigation
• Long-term exposure reduction
32) How do you think about blast radius?
Focus: Containment strategy
Core Idea: Fail safely, not perfectly
Strong answers cover:
• Isolation techniques
• Least privilege
• Recovery time objectives
• Organisational resilience
33) How do you design systems assuming breach?
Focus: Defensive realism
Core Idea: Breach is inevitable
Strong answers cover:
• Lateral movement prevention
• Detection-first mindset
• Recovery planning
• Long-term survivability
34) How do you evaluate new security tools or frameworks?
Focus: Tool judgment
Core Idea: Tools don’t fix bad thinking
Strong answers cover:
• Risk reduction vs complexity
• Integration cost
• Developer trust
• Long-term maintainability
35) How do you communicate risk to non-technical stakeholders?
Focus: Leadership communication
Core Idea: Security fails when it can’t be explained
Strong answers cover:
• Business impact framing
• Clear tradeoffs
• Metrics that matter
• Executive trust
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E) Detection Engineering & Incident Response (36–43)
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36) How do you design a detection strategy?
Focus: Visibility
Core Idea: Detection beats prevention alone
Strong answers cover:
• Signal-to-noise ratio
• Coverage gaps
• Cost tradeoffs
• Continuous improvement
37) What logs are most important for security?
Focus: Observability
Core Idea: Logs are your memory
Strong answers cover:
• Identity events
• Privilege changes
• Control-plane activity
• Long-term forensic value
38) How do you reduce alert fatigue?
Focus: Operational maturity
Core Idea: Burned-out teams miss real attacks
Strong answers cover:
• Alert quality metrics
• Context enrichment
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If you’re serious about senior or staff-level security roles, notice the pattern across all of these questions: interviewers are not looking for perfect answers, they’re looking for how you think.
Can you reason about tradeoffs?
Can you explain risk in business terms?
Can you design systems that fail safely?
Can you scale security without becoming the bottleneck?
In future newsletters, I’ll break down sample “strong answers” to several of these questions and explain why certain responses consistently pass senior-level interviews while others don’t.
If this was useful, consider sharing it with someone preparing for security interviews — and if you’re new here, welcome. You’re in the right place.