Q: Your S3 bucket is publicly accessible and AWS sent you a security alert. How do you fix it?
1. Block Public Access settings — go to S3 → Block Public Access → Enable all four settings. This overrides any bucket/object ACLs and po...
#AWS #S3 & Storage #L2 #Cloud #Infrastructure #S3
🎙️ Candidate Opening & Architectural Context
""AWS reliability requires differentiating between AWS control plane limits and host-level resource exhaustion. When addressing this question, I walk the interviewer through our production incident runbook: isolating the blast radius, checking diagnostic logs and metrics, and applying a safe fix.""
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Initial Diagnostics & Root Cause Analysis
For legitimate public content (website assets): use CloudFront in front of a private S3 bucket instead of making the bucket public directly.
- Block Public Access settings — go to S3 → Block Public Access → Enable all four settings. This overrides any bucket/object ACLs and policies that grant public access.
- Review bucket policy — remove any
Principal: *statements. - Review object ACLs — remove
public-readACLs from objects.
2️⃣
Remediation & Permanent Safeguards
- Check for misconfigured static website hosting — if not needed, disable it.
- Enable S3 Access Analyzer — finds all resource policies that allow external access.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Pro-Tip: Block Public Access settings — go to S3 → Block Public Access → Enable all four settings. This overrides any bucket/object ACLs an."
⚡ 60-Second Elevator Pitch Talking Points
- Block Public Access settings — go to S3 → Block Public Access → Enable all four settings. This ov...
- Review bucket policy — remove any Principal: * statements.
- Review object ACLs — remove public-read ACLs from objects.
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