- Malicious actor encrypts files:
An attacker uses compromised credentials to access an S3 bucket, encrypting files and leaving a ransom note demanding payment in cryptocurrency.
- Over-permissioned application misbehaves:
A misconfigured script with excessive permissions accidentally overwrites critical files during a bulk operation, mimicking ransomware behavior.
AWS Suspect Public S3 Change
Detection overview
The AWS Ransomware S3 Activity detection identifies suspicious interactions with Amazon S3 buckets that align with ransomware-like behavior. Ransomware campaigns in cloud environments can target S3 storage to encrypt or delete data, disrupting business continuity and demanding ransoms for decryption keys. This detection is essential for protecting critical cloud resources and data from malicious actors exploiting the flexibility of S3 for large-scale attacks.
Triggers
- A credential was observed suspiciously invoking a set of S3 APIs that permits public access to a given bucket.
Possible Root Causes
- An attacker may be scanning and maliciously modifying configurations around an S3 bucket to enable data exfiltration.
- An IT misconfiguration may have been made by an authorized user which could weaken the posture around an S3 bucket and promote the risk of data loss. • An internal tool is scanning the buckets for security reasons.
Business Impact
- Malicious or unintentional weakening of security posture controls around S3 buckets are commonly associated with data loss.
Steps to Verify
- Investigate the account context that made the change for other signs of malicious activity.
- Investigate for data loss.
- Verify if the S3 bucket in question is authorized for public access.
- If review indicates possible malicious actions or high-risk configuration, revert configuration and disable credentials associated with this alert then perform a comprehensive investigation.
AWS Suspect Public S3 Change
Possible root causes
Malicious Detection
An attacker gains access to AWS credentials or exploits an application with S3 permissions, initiating ransomware attacks to encrypt files. This activity aims to disrupt access and demand ransom payments for decrypting vital business data.
Benign Detection
The behavior could result from legitimate bulk data operations, such as backups, migrations, or software deployments involving mass file updates in S3. Developers or automated workflows might inadvertently mimic ransomware patterns during these processes.
AWS Suspect Public S3 Change
Example scenarios
AWS Suspect Public S3 Change
Business impact
If this detection indicates a genuine threat, the organization faces significant risks:
Data loss and service disruption
Encrypted or deleted files can result in loss of critical business information and halt operational processes.
Financial implications
Paying ransoms or recovering from ransomware attacks can incur significant financial costs.
Reputation damage
A ransomware attack targeting cloud infrastructure could tarnish the organization's reputation, undermining customer trust.
AWS Suspect Public S3 Change
Steps to investigate
Analyze access patterns
Review the detection details and logs to identify unusual access or operations within S3 buckets.
Verify user intent
Determine if the activity was initiated by a legitimate user or application. Confirm if the intent aligns with routine operations.
Inspect IAM policies
Ensure the roles and permissions of the affected users or applications are appropriately scoped to prevent misuse.
Check for ransom indicators
Look for ransom notes or encrypted files with suspicious extensions in the affected buckets.
AWS Suspect Public S3 Change