Listen to this Post
A while ago, a cloud engineer was grilled about a high AWS billātoo many NAT gateways, zombie EC2 instances, and forgotten RDS snapshots. But beyond the cost, the real concern was security. Every idle resource is an unmonitored liability, and unexpected cost spikes could indicate a breach.
Cloud cost management isnāt just about saving moneyāitās about reducing attack surfaces. Untagged assets, orphaned services, and unused resources create blind spots for attackers. By analyzing cloud bills, security teams can detect drift, while finance teams uncover unowned risks.
You Should Know: AWS Security Hardening & Cost Optimization Commands
1. Identify & Terminate Zombie EC2 Instances
aws ec2 describe-instances --query 'Reservations[].Instances[?State.Name==<code>stopped</code>].[InstanceId, Tags]' --output text aws ec2 terminate-instances --instance-ids i-1234567890abcdef0
2. Clean Up Unused EBS Volumes
aws ec2 describe-volumes --filters Name=status,Values=available --query 'Volumes[].VolumeId' --output text | xargs -I {} aws ec2 delete-volume --volume-id {}
3. Delete Old RDS Snapshots
aws rds describe-db-snapshots --query 'DBSnapshots[?SnapshotCreateTime<=<code>2024-01-01</code>].DBSnapshotIdentifier' --output text | xargs -I {} aws rds delete-db-snapshot --db-snapshot-identifier {}
4. Detect Unused NAT Gateways
aws ec2 describe-nat-gateways --query 'NatGateways[?State==<code>failed</code> || State==<code>deleted</code>].NatGatewayId' --output text
- Monitor Cost Anomalies (AWS Cost Explorer API)
aws ce get-cost-and-usage --time-period Start=2024-01-01,End=2024-01-31 --granularity MONTHLY --metrics "UnblendedCost" --group-by Type=DIMENSION,Key=SERVICE
6. Enforce Tagging Policies
aws organizations create-policy --name "EnforceTagging" --description "Mandatory tags for all resources" --content file://tagging-policy.json
7. Detect Unauthorized API Calls (CloudTrail)
aws cloudtrail lookup-events --lookup-attributes AttributeKey=EventName,AttributeValue=RunInstances --start-time "2024-01-01T00:00:00Z" --end-time "2024-01-31T23:59:59Z"
What Undercode Say
Cloud cost anomalies are early breach indicators. Unmonitored resourcesālike forgotten snapshots and idle instancesāare low-hanging fruit for attackers. By automating cleanup and enforcing tagging, organizations reduce both costs and risks.
Security teams should integrate AWS CLI checks into CI/CD pipelines, while finance teams must treat billing spikes as security alerts. Combining `aws-nuke` for resource cleanup and AWS Security Hub for continuous monitoring ensures a lean, secure cloud environment.
Expected Output:
- Reduced AWS bill via automated cleanup scripts.
- Fewer attack vectors by eliminating unused resources.
- Improved compliance with enforced tagging policies.
- Faster breach detection via cost anomaly alerts.
Further Reading:
- AWS Cost Optimization Best Practices
- AWS Security Command Reference
- Automating Cloud Hygiene with AWS-Nuke
References:
Reported By: Danielgrzelak A – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ā
