modbender AWS Security Scanner
Audit AWS infrastructure for security issues using AWS CLI.
Prerequisites
- AWS CLI configured (
aws configureor IAM role) - Read permissions for resources being scanned
Quick Scans
S3 Bucket Security
# Find public buckets
aws s3api list-buckets --query 'Buckets[].Name' --output text | tr '\t' '\n' | while read bucket; do
acl=$(aws s3api get-bucket-acl --bucket "$bucket" 2>/dev/null)
policy=$(aws s3api get-bucket-policy --bucket "$bucket" 2>/dev/null)
public_access=$(aws s3api get-public-access-block --bucket "$bucket" 2>/dev/null)
echo "=== $bucket ==="
echo "$acl" | grep -q "AllUsers\|AuthenticatedUsers" && echo "⚠️ PUBLIC ACL"
echo "$policy" | grep -q '"Principal":"\*"' && echo "⚠️ PUBLIC POLICY"
echo "$public_access" | grep -q "false" && echo "⚠️ Public access not fully blocked"
done
IAM Security Issues
# Users without MFA
aws iam generate-credential-report && sleep 5
aws iam get-credential-report --query 'Content' --output text | base64 -d | grep -E "^[^,]+,.*,false" | cut -d',' -f1
# Overly permissive policies (Admin access)
aws iam list-policies --scope Local --query 'Policies[].Arn' --output text | tr '\t' '\n' | while read arn; do
version=$(aws iam get-policy --policy-arn "$arn" --query 'Policy.DefaultVersionId' --output text)
aws iam get-policy-version --policy-arn "$arn" --version-id "$version" --query 'PolicyVersion.Document' | grep -q '"Action":"\*".*"Resource":"\*"' && echo "⚠️ Admin policy: $arn"
done
# Access keys older than 90 days
aws iam list-users --query 'Users[].UserName' --output text | tr '\t' '\n' | while read user; do
aws iam list-access-keys --user-name "$user" --query "AccessKeyMetadata[?CreateDate<='$(date -d '-90 days' +%Y-%m-%d)'].{User:UserName,KeyId:AccessKeyId,Created:CreateDate}" --output table
done
Security Groups
# Open to world (0.0.0.0/0)
aws ec2 describe-security-groups --query 'SecurityGroups[?IpPermissions[?IpRanges[?CidrIp==`0.0.0.0/0`]]].{ID:GroupId,Name:GroupName,VPC:VpcId}' --output table
# SSH open to world
aws ec2 describe-security-groups --filters "Name=ip-permission.from-port,Values=22" "Name=ip-permission.cidr,Values=0.0.0.0/0" --query 'SecurityGroups[].{ID:GroupId,Name:GroupName}' --output table
# RDP open to world
aws ec2 describe-security-groups --filters "Name=ip-permission.from-port,Values=3389" "Name=ip-permission.cidr,Values=0.0.0.0/0" --query 'SecurityGroups[].{ID:GroupId,Name:GroupName}' --output table
CloudTrail Status
# Check if CloudTrail is enabled in all regions
aws cloudtrail describe-trails --query 'trailList[].{Name:Name,IsMultiRegion:IsMultiRegionTrail,LogValidation:LogFileValidationEnabled,S3Bucket:S3BucketName}' --output table
# Check for trails without log validation
aws cloudtrail describe-trails --query 'trailList[?LogFileValidationEnabled==`false`].Name' --output text
RDS Security
# Publicly accessible RDS instances
aws rds describe-db-instances --query 'DBInstances[?PubliclyAccessible==`true`].{ID:DBInstanceIdentifier,Engine:Engine,Endpoint:Endpoint.Address}' --output table
# Unencrypted RDS instances
aws rds describe-db-instances --query 'DBInstances[?StorageEncrypted==`false`].{ID:DBInstanceIdentifier,Engine:Engine}' --output table
EBS Encryption
# Unencrypted EBS volumes
aws ec2 describe-volumes --query 'Volumes[?Encrypted==`false`].{ID:VolumeId,Size:Size,State:State}' --output table
Full Audit Report
Run comprehensive scan and output markdown report:
echo "# AWS Security Audit Report"
echo "Generated: $(date)"
echo ""
echo "## S3 Buckets"
# ... run S3 checks
echo ""
echo "## IAM"
# ... run IAM checks
echo ""
echo "## Security Groups"
# ... run SG checks
# etc.
Severity Levels
| Issue | Severity |
|---|---|
| S3 bucket public | 🔴 Critical |
| SSH/RDP open to world | 🔴 Critical |
| IAM user without MFA | 🟠 High |
| Admin policy attached | 🟠 High |
| CloudTrail disabled | 🟠 High |
| RDS publicly accessible | 🟠 High |
| Unencrypted EBS/RDS | 🟡 Medium |
| Access keys > 90 days | 🟡 Medium |
CIS Benchmark Checks
For comprehensive CIS AWS Foundations Benchmark compliance, check:
- 1.1: Avoid root account usage
- 1.2: MFA on root
- 1.3: Disable unused credentials
- 2.1: CloudTrail enabled
- 2.2: Log file validation
- 4.1: No security groups allow 0.0.0.0/0 to port 22
- 4.2: No security groups allow 0.0.0.0/0 to port 3389
Automation
For scheduled scans, use AWS Config Rules or set up cron:
0 6 * * * /path/to/aws-security-scan.sh | mail -s "Daily AWS Audit" security@company.com