Privacy Audit Skill

Goal

Ensure no PII leaks, all data flows are documented, and the codebase complies with applicable data protection regulations (GDPR, CCPA, HIPAA). Produce a data flow map and violation list.

Steps

1. Identify applicable regulations

   • Ask if unclear: "Which regulations apply to this project?" (GDPR, CCPA, HIPAA, PIPEDA, LGPD)
   • GDPR: European users or EU data processing
   • CCPA: California users
   • HIPAA: US healthcare data (PHI)

2. Scan codebase for PII exposure

   Automated scanning:

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   # Semgrep with PII detection rules
   npx semgrep --config=p/pii src/
   
   # Search for common PII patterns in logs/error handlers
   grep -rn "console.log\|logger\." src/ | grep -i "email\|name\|phone\|address\|ssn\|dob"
   

   Manual checks — scan for these patterns:

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   In log statements: email, name, phone number, IP address, user ID with PII
   In error messages: SQL errors with PII data, stack traces with user context
   In analytics events: user identifiers beyond anonymized IDs
   In API responses: unnecessary PII fields (returning full user object when only ID needed)
   

3. Map all data flows

   Create a data flow inventory:

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   | Data Element | Collected At | Stored In | Processed By | Transmitted To | Deleted When |
   |---|---|---|---|---|---|
   | Email address | Registration form | users table | Auth service | SendGrid (email delivery) | Account deletion |
   | IP address | Every request | access_logs table | Rate limiter | None | 90 days |
   | Payment card | Checkout | NEVER (tokenized) | Stripe | Stripe only | N/A (tokenized) |
   

4. Check consent mechanisms

   • Is explicit consent obtained before collecting any personal data?
   • Is consent granular? (can users opt out of marketing while keeping functional data?)
   • Is consent recorded? (timestamp, what was consented to, which version of privacy policy)
   • Can consent be withdrawn? Is there a clear opt-out mechanism?

5. Check data minimization

   • Is only the minimum necessary data collected?
   • Are there fields in the database that are collected but never used?
   • Are analytics events capturing unnecessary user identifiers?

6. Check data retention

   • Are there defined retention periods for all data categories?
   • Is there an automated deletion process for expired data?
   • Does the system support "right to erasure" (GDPR Article 17)?
   • Are backups excluded from the erasure process? (This is a common gap)

7. Check data subject rights (GDPR/CCPA)

   • Right to access: can users export their data?
   • Right to erasure: can users delete their account and data?
   • Right to portability: can data be exported in machine-readable format?
   • Right to rectification: can users correct their data?

8. Check encryption

   • PII encrypted at rest in database? (column-level encryption for sensitive fields)
   • PII encrypted in transit? (TLS everywhere)
   • Are database backups encrypted?
   • Are any PII fields stored in plaintext where they shouldn't be?

9. Check third-party data sharing

   • Is a data processing agreement (DPA) in place with each third party that receives PII?
   • Are users informed of third-party data sharing in the privacy policy?
   • Is there a list of all sub-processors maintained?

10. Generate privacy audit report

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    ## Privacy Audit Report
    
    ### Regulations Applicable: [GDPR / CCPA / HIPAA]
    
    ### PII Exposure Findings
    - [CRITICAL] Email address logged at src/middleware/logger.ts:42
    - [HIGH] API response includes full user object — filter to minimum needed fields
    
    ### Data Flow Map
    [see attached or inline table]
    
    ### Consent Mechanism: [COMPLIANT / NON-COMPLIANT]
    - Issue: No consent recorded for marketing emails
    
    ### Data Retention: [COMPLIANT / NON-COMPLIANT]
    - Issue: access_logs never deleted (retention policy not implemented)
    
    ### Encryption: [COMPLIANT / NON-COMPLIANT]
    - Issue: phone_number stored in plaintext — should use field encryption
    
    ### Data Subject Rights: [COMPLIANT / NON-COMPLIANT]
    - Issue: No data export endpoint (required by GDPR Article 20)
    
    ### Recommended Actions (priority order)
    1. [CRITICAL] Remove email from log statements
    2. [HIGH] Implement data retention cleanup job
    3. [HIGH] Add data export endpoint
    

Constraints

• Critical PII exposure findings are always blocking for regulated industries
• Data flow map must be maintained and updated as the codebase evolves
• Any new feature handling PII must trigger a privacy review before implementation
• Do not add privacy controls without documenting why (regulatory requirement or privacy-by-design)

Output Format

Privacy audit report + data flow map document at docs/privacy/data-flow-map.md.