Cloud Chaos: Ransomware Campaign Threatens Businesses Using AWS S3 Storage

 April 16, 2025

A large-scale ransomware campaign has sent shockwaves through the tech world as attackers reportedly gained unauthorized access to thousands of AWS S3 storage buckets, compromising sensitive data from businesses across multiple sectors.

Thousands of Access Keys Leaked

Cybersecurity experts have confirmed that threat actors obtained thousands of AWS access keys, potentially through exposed credentials on public GitHub repositories, misconfigured CI/CD pipelines, or phishing attacks. Once armed with the keys, the attackers accessed Amazon S3 (Simple Storage Service) storage buckets and either encrypted the contents or exfiltrated data before leaving ransom demands.

Victims Across the Globe

Companies from the United States, Europe, and Asia have reported disruptions ranging from temporary data loss to full outages of customer-facing applications. Many organizations store backups, sensitive files, and operational data on S3, making it a high-value target for attackers.

Cybersecurity firm CloudSentinel estimates that over 5,000 businesses may be affected, and some have already received ransom notes demanding payments in cryptocurrency, with threats of leaking stolen data if demands aren’t met within 72 hours.

Amazon Responds

Amazon Web Services has acknowledged the incident but clarified that the core S3 infrastructure was not breached.

“The attacks appear to be the result of compromised credentials, not a vulnerability in AWS systems,” an AWS spokesperson stated. “We strongly encourage users to rotate access keys, implement multi-factor authentication, and audit permissions immediately.”

How It Happened

Security analysts believe the campaign may be orchestrated by a previously unknown ransomware group that specializes in exploiting cloud environments. They reportedly used automated tools to scan for exposed access keys and immediately target linked S3 buckets.

The attackers used a technique known as “bucket encryption and ransom chaining” — where they download and delete the original data, encrypt it locally, and re-upload encrypted versions to the same buckets with ransom instructions.

Recommendations for Protection

Cybersecurity experts are urging organizations to take the following steps:

• Audit all AWS IAM users and keys for suspicious activity

• Immediately rotate access keys and limit their scope

• Enable MFA on all root and IAM accounts

• Set up automated alerts for unusual S3 access patterns

• Avoid hardcoding credentials in codebases or public repositories

Growing Trend

This incident is part of a growing trend in which ransomware groups shift their focus from on-premises infrastructure to the cloud, recognizing that cloud misconfigurations and leaked credentials offer lucrative opportunities with minimal resistance.

As cloud adoption increases, experts warn that similar attacks may become more frequent and sophisticated.

“This is a wake-up call for every company relying on the cloud,” said cybersecurity analyst Lena Martinez. “Strong security hygiene and proactive monitoring are no longer optional—they’re essential.”