S3 Bucket Policy Project 9: Deny Delete, MFA Delete आणि Object Lock

By Ravindra Bagale, trainer · LinkedIn · Last updated: 28 October 2026

1. Story

Rohit Verma (दिल्ली) व Erik Lindqvist (Stockholm) disk images. Accidental rm नको.

2. का?

हे का लागतं?

Versioning पुरेसं नाही. MFA Delete + Object Lock = friction + WORM.

• MFA condition
• MFA Delete
• Lock modes
• Plan retention

3. Policy

हे काय आहे?

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "DenyDeleteWithoutMFA",
      "Effect": "Deny",
      "Principal": "*",
      "Action": [
        "s3:DeleteObject",
        "s3:DeleteObjectVersion",
        "s3:PutLifecycleConfiguration"
      ],
      "Resource": [
        "arn:aws:s3:::rb-evidence-ap-south-1",
        "arn:aws:s3:::rb-evidence-ap-south-1/*"
      ],
      "Condition": {
        "BoolIfExists": { "aws:MultiFactorAuthPresent": "false" }
      }
    }
  ]
}

Line-by-line

1. Delete without MFA.
2. Lifecycle lock.
3. MFA missing.
4. Lock separate.
5. Root MFA Delete.
6. Compliance hard.

4. CLI

कसं करायचं (step by step)

# Versioning + Object Lock must be set at create time for Lock
aws s3api create-bucket --bucket rb-evidence-ap-south-1 --region ap-south-1 \
  --create-bucket-configuration LocationConstraint=ap-south-1 \
  --object-lock-enabled-for-bucket

aws s3api put-bucket-policy --bucket rb-evidence-ap-south-1 --policy file://deny-delete.json

# MFA Delete (example — requires root serial/token; lab carefully)
# aws s3api put-bucket-versioning --bucket rb-evidence-ap-south-1 \
#   --versioning-configuration Status=Enabled,MFADelete=Enabled \
#   --mfa "arn:aws:iam::111122223333:mfa/root-account-mfa-device PASSCODE"

5. Allow/deny

# DENY — normal session delete
aws s3 rm s3://rb-evidence-ap-south-1/disk.img
# AccessDenied

# ALLOW — session with MFA (STS get-session-token with MFA, then delete)
aws sts get-session-token --serial-number arn:aws:iam::111122223333:mfa/user --token-code 123456
# export temp keys, then:
aws s3 rm s3://rb-evidence-ap-south-1/disk.img
# delete success (unless Object Lock retention still blocks)

6. Object Lock

7. Multi-industry

Forensics, cyber, SOC, pharma.

8. AccessDenied debugging आणि Policy Simulator

AccessDenied क्रम: BPA → bucket Deny → IAM Allow → KMS → VPCe → ACL. Simulator BPA/VPC/KMS miss करू शकतो — खऱ्या CLI ने test.

# Decode
aws s3api get-bucket-policy --bucket BUCKET --query Policy --output text | python3 -m json.tool
aws s3api get-public-access-block --bucket BUCKET
aws iam simulate-principal-policy --policy-source-arn ARN \
  --action-names s3:GetObject --resource-arns arn:aws:s3:::BUCKET/key.txt
aws cloudtrail lookup-events --lookup-attributes AttributeKey=EventName,AttributeValue=GetObject --max-items 5

9. Lab: deny delete MFA

Org block नसेल तर ap-south-1 (Mumbai). आधी budget alert.

कसं करायचं (step by step)

1. Create bucket.
2. Policy + upload.
3. Deny proof.
4. MFA/Lock allow path.

Cleanup (billing थांबवा)

1. Careful cleanup.
2. Avoid endless Compliance.

10. सामान्य errors आणि fixes

प्रत्येक row = खरी चूक. Panic करण्याआधी fix वाचा.

11. Troubleshooting checklist

1. Region + endpoint.
2. Policy + BPA.
3. Lab user.
4. Sid binary search.
5. CloudTrail.
6. KMS test.
7. VPCe path.
8. Lock cleanup.

12. FAQ

13. Interview Q&A

14. Tips — English, मराठी आणि हिंदी

15. Policy save करण्याआधी checklist

1. Business rule एका वाक्यात.
2. Allow vs Deny-unless; Deny wins.
3. ARN shapes.
4. Condition keys.
5. BPA first.
6. Allow+deny plan.
7. Cleanup plan.
8. json.tool.

16. Policy Simulator walkthrough

Simulator identity/resource typos साठी चांगला; BPA/VPCe/KMS miss होऊ शकतात. नंतर खऱ्या path वरून CLI.

1. Simulator → user/role.
2. Action + ARN.
3. Include bucket policy.
4. CLI confirm.
5. Mismatch → layers.

17. Copy-paste runbook

# 0) Region + names
export AWS_REGION=ap-south-1
export BUCKET=rb-lab-$(date +%s)-ap-south-1

# 1) Create + show BPA
aws s3api create-bucket --bucket $BUCKET --region $AWS_REGION \
  --create-bucket-configuration LocationConstraint=$AWS_REGION
aws s3api get-public-access-block --bucket $BUCKET || true

# 2) Validate + apply policy
python3 -m json.tool policy.json >/dev/null
aws s3api put-bucket-policy --bucket $BUCKET --policy file://policy.json
aws s3api get-bucket-policy --bucket $BUCKET --query Policy --output text | python3 -m json.tool | head

# 3) Allow test + Deny test (fill per project)
# ... project-specific curls / aws s3 cp ...

# 4) Cleanup
aws s3 rm s3://$BUCKET --recursive || true
aws s3api delete-bucket-policy --bucket $BUCKET || true
aws s3api delete-bucket --bucket $BUCKET

18. Industry story bank

वरील प्रत्येक project एक industry story वापरतो. इतर industries मध्ये फक्त bucket/principal/Condition बदला.

• Healthcare: SSE-KMS + OrgID + MFA.
• Fintech: IP + HTTPS + OAC.
• EdTech: OAC only.
• Logistics: VPCe.
• Media: Object Lock.
• Retail: prefix public read.
• SaaS: prefix homes.
• Gov: OrgID + MFA + Lock.

19. AccessDenied debugging flowchart

1. Error code + request id.
2. Bucket + region.
3. BPA.
4. Explicit Deny.
5. Conditions.
6. KMS key policy.
7. OAC id.
8. VPCe path.
9. Simulator + CLI.
10. Support last.

20. PR review checklist

• Valid JSON.
• Required fields.
• No open write.
• Tests.
• Cleanup.

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