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14. Amazon S3: Buckets, Objects, Policies and Presigned URLs

14.4 Hosting a Static Website on S3

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HTML, CSS, JS aani images astil (server-side code nahi) tar S3 varun website chalavta yete – server nahi, patching nahi. Ha ekach bucket asa aahe jithe aapan jaanun-bujun public read deto.

BUCKET=ravindra-static-site-nashik
aws s3 mb s3://$BUCKET --region ap-south-1
aws s3 sync ./site s3://$BUCKET/                      # index.html, error.html, css/, img/
aws s3 website s3://$BUCKET/ --index-document index.html --error-document error.html
# allow public policies on THIS bucket only (console: Permissions → Block public access → Edit)
aws s3api put-public-access-block --bucket $BUCKET \
  --public-access-block-configuration BlockPublicAcls=true,IgnorePublicAcls=true,BlockPublicPolicy=false,RestrictPublicBuckets=false

Public read policy – only GetObject, never ListBucket or PutObject:

{
  "Version": "2012-10-17",
  "Statement": [{
    "Sid": "PublicReadWebsite",
    "Effect": "Allow",
    "Principal": "*",
    "Action": "s3:GetObject",
    "Resource": "arn:aws:s3:::ravindra-static-site-nashik/*"
  }]
}

The website endpoint looks like http://ravindra-static-site-nashik.s3-website.ap-south-1.amazonaws.com. Note: the S3 website endpoint is HTTP only. For HTTPS and your own domain, put CloudFront in front of the bucket (with Origin Access Control, so the bucket itself can stay private) and point www.yourdomain.com to CloudFront with a CNAME.

Option HTTPS Bucket public? Use for
S3 website endpoint No Yes (read only) Quick demos, learning
CloudFront + OAC Yes, custom domain No – only CloudFront can read Real production static sites
Nginx on EC2 (Part 3) Yes with Certbot Not applicable When you also need server-side code

Ravindra Bagale's Tip

Students accidentally sync .env, backup.zip and the .git folder into the website bucket too – and they become public! Use excludes, like aws s3 sync ./site s3://bucket/ --exclude ".git/*" --exclude "*.env" --exclude "*.zip". After uploading, always check once with aws s3 ls --recursive what has become public.

Lab

Host a two-page static site (index.html, about.html, error.html) on S3. Open the website endpoint, open a wrong URL to see error.html, then try aws s3 ls s3://<bucket> without credentials (--no-sign-request) and confirm listing is refused while pages still load.

Extended teaching notes

Why this lesson matters

Use this lesson to strengthen systems you own: understand the risk, practise safely in a lab, then write and apply the fix.

Apply the fix across stacks

Same class of bug, same idea in every language.

Java / Spring Boot

Parameterise queries, encode output, CSRF tokens, limited Actuator, dependency scanning.

ASP.NET Core

EF Core / parameterised SQL, Razor encoding, HTTPS, Data Protection.

Node.js / Express

helmet, parameterised SQL, npm audit, avoid eval and shell concat.

Python / Django / Flask / FastAPI

ORM, autoescape, pip-audit, Bandit; never shell=True with user input.

PHP / Laravel

PDO/Eloquent, Blade escaping, composer audit.

Go / Ruby

database/sql placeholders / ActiveRecord; html/template / ERB escaping; govulncheck / Brakeman.

nginx / Apache / Tomcat

Hide versions, TLS, security headers, least-open ports.

MySQL / PostgreSQL / MongoDB / Redis

Private networks, auth on, least-privilege users, no 0.0.0.0/0.

AWS / Azure / GCP

Roles not long-lived keys, private data stores, cloud audit logs on.

Mini case study

Suppose we are on a purple-team exercise for an Indian mid-size company (sample data). Red notes a technique from this lesson against a lab clone. Blue must show the control that stops it, the log that would have fired, and the ticket that hardens production. That is the standard this course trains you for.

Defender's worksheet (do this today)

  1. Write the lesson title, date and the exact lab target you are allowed to use.
  2. List three owned systems (VMs, apps, or cloud accounts) where this lesson applies.
  3. Run one safe check from the lesson on a lab system only. Paste the command and output.
  4. Write a two-sentence fix you would give a teammate.
  5. Name one related public advisory (CERT-In, CISA, NVD, or a vendor bulletin) with its date.

Indian workplace (sample data)

Suppose we are a junior analyst at Infosys, TCS, Wipro or a fintech SOC in Bengaluru/Pune. Turn this lesson into one checklist item with an owner, a due date and a place to store evidence (ticket + screenshot).

Global practice

Compare your notes with OWASP, CIS Benchmarks, NIST CSF/IR guidance or a cloud Well-Architected security question. Write five lines on what overlaps.

Everyday analogy

Explain the risk and the fix to a family member without jargon. If they can repeat the warning, you understand it well enough to teach juniors.

Key terms

  • Control: a safeguard (patch, config, process, detection).
  • Finding: a weakness backed by evidence.
  • Remediation: the fix plus how you verified it.
  • Scope: systems you have written permission to touch.
  • Least privilege: only the access the task needs.
  • Defence in depth: several layers so one failure does not end the story.

Common mistakes

  • Skipping written permission "just for a quick scan".
  • Practising on hostel, office or public targets without authorisation.
  • Collecting tool output without writing the fix.
  • Copying attack steps onto production to "verify". Defenders verify with versions, configs and patches.
  • Publishing screenshots that contain secrets, cookies or internal hostnames.

Recap

  • Evidence, fix, owner, date.
  • Own lab only.
  • Fix > spectacle.