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Cloud Misconfigurations: The Silent Killer

8 min readK4L1 Security

The most dangerous cloud misconfigurations I find repeatedly — and how to detect them before attackers do.

S3 Bucket Misconfigurations

The most common cloud misconfiguration I find is publicly accessible S3 buckets. Not just read access — in many cases, buckets have write access enabled, allowing anyone to upload malicious files or overwrite existing data. Always enable 'Block Public Access' at the account level and use bucket policies to explicitly deny public access.

Overly Permissive IAM Policies

IAM policies with '*' in the Resource or Action fields are a red flag. I routinely find service accounts with full administrative access, lambda execution roles that can modify any resource, and cross-account trust policies that allow any AWS account to assume a role. Follow least privilege — grant only the permissions needed for the specific task.

Exposed Database Ports

Security groups allowing inbound access to database ports (3306, 5432, 27017) from 0.0.0.0/0 are still shockingly common. These databases often have default or weak credentials. Database access should be restricted to specific IP ranges and routed through VPN or bastion hosts.

Missing Encryption

Data at rest and in transit should always be encrypted. I frequently find unencrypted EBS volumes, S3 objects, and RDS snapshots. Enable default encryption on all S3 buckets, use KMS customer-managed keys for sensitive data, and enforce TLS for all database connections.

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K4L1 Security

Bug Bounty Hunter & Security Researcher

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