The Silent Data Leak - Exfiltrating AWS Snapshots and Why It’s a Hacker’s Dream

In cloud environments, data exfiltration often presents a significant risk to organizations. Among the many ways attackers can exfiltrate sensitive data, leveraging snapshots in AWS is particularly stealthy and can lead to serious consequences. This article explores how attackers exploit snapshots, why it can be difficult to uncover, and what organizations can do to mitigate this threat.

What Are Snapshots in AWS?

Snapshots in AWS are backups of the data volumes (EBS - Elastic Block Store) that store critical data for applications. They allow users to create point-in-time copies of their volumes, enabling quick recovery from data loss, application deployment across multiple regions, or scaling up environments. Snapshots can be shared between AWS accounts, and they play a crucial role in maintaining data redundancy and availability.

How Attackers Exfiltrate Snapshots

1. Creating and Sharing Snapshots with a Compromised Account

One common attack method involves creating snapshots of EBS volumes and sharing them with external accounts. If an attacker gains access to an account with sufficient permissions, they can create snapshots of any critical volume, such as databases or file storage, and share them with an account they control. Once shared, the attacker can copy the snapshot to their environment, effectively exfiltrating the data.

2. Cross-Region Replication of Snapshots

Another tactic is to replicate snapshots to another AWS region. By doing this, the attacker can bypass monitoring tools that might be region-specific. Once the snapshots are replicated, they can be shared or downloaded from a different region, making it difficult to track the unauthorized movement of data.

3. Using IAM Roles and Temporary Credentials

Attackers can exploit compromised IAM roles with permissions to create and share snapshots. By using temporary credentials, they can execute these actions without leaving behind significant evidence, further masking their activities. For example, an attacker might create an IAM role with limited permissions to avoid suspicion, but still include snapshot operations.

Why Is It So Difficult to Uncover?

1. Legitimate Use Cases Make Detection Challenging

Snapshots are commonly used for backup, disaster recovery, and environment scaling. Because of their legitimate applications, the creation and sharing of snapshots might not raise immediate red flags. Without proper monitoring, distinguishing between normal activity and malicious behavior can be extremely difficult.

2. Lack of Visibility Across Accounts and Regions

AWS accounts often span multiple regions, making it easy for attackers to operate in regions not actively monitored. Furthermore, security teams may focus on the primary account without accounting for the possibility of data being shared or copied to external accounts. This lack of cross-account and cross-region visibility can lead to missed exfiltration attempts.

3. Stealthy IAM Role Exploitation

Attackers may use sophisticated techniques to exploit IAM roles, such as chaining roles across multiple services or assuming roles temporarily. These actions can be challenging to trace, particularly if the roles have been configured to perform snapshot-related tasks as part of their normal operation.

Relevant MITRE ATT&CK Techniques

The techniques related to AWS snapshot exfiltration align closely with the MITRE ATT&CK framework:

• T1003.008 - OS Credential Dumping: Cloud Instance Metadata API: Attackers might exploit cloud instance metadata to obtain temporary credentials, enabling them to interact with AWS services.

• T1530 - Data from Cloud Storage Object: This technique encompasses data exfiltration methods involving cloud storage, which can include snapshots.

• T1078 - Valid Accounts: Attackers leverage valid accounts, including stolen credentials, to create snapshots and share them externally.

• T1537 - Transfer Data to Cloud Account: Attackers might transfer data by creating snapshots and copying them to different accounts or regions.

Why Snapshot Exfiltration Can Be a Game Over

Snapshot exfiltration can lead to "game over" scenarios for several reasons:

1. Direct Access to Critical Data: Snapshots contain the exact data from volumes, including databases, sensitive files, and application configurations. An attacker who exfiltrates a snapshot essentially obtains a copy of all the data on the volume, which can include sensitive information, customer data, intellectual property, and more.

2. Low Detection: If the attacker has set up snapshots to be automatically replicated or shared across accounts, they can retrieve data over time without triggering significant alerts. Once the data is out of the organization's control, it becomes challenging to assess and mitigate the breach.

3. Further Attacks Enabled by Stolen Data: Access to sensitive data can lead to subsequent attacks, such as ransomware, financial fraud, or identity theft, amplifying the damage beyond the initial data breach.

Mitigation Strategies

1. Implement Least Privilege IAM Policies

   • Ensure that IAM roles and users only have the permissions they need. Restrict access to the ec2:CreateSnapshot, ec2:CopySnapshot, and ec2:ModifySnapshotAttribute actions to trusted roles. Use the principle of least privilege to minimize the attack surface.

2. Enable CloudTrail and Monitor Snapshot Operations

   • Use AWS CloudTrail to monitor and log all snapshot-related activities. Look for actions like CreateSnapshot, ShareSnapshot, and ModifySnapshotAttribute to detect unusual behavior. Setting up alerts for these activities can help security teams respond quickly to suspicious actions.

3. Regularly Audit and Review IAM Roles

   • Regular audits of IAM roles and permissions can help identify excessive privileges and potential security gaps. Use AWS IAM Access Analyzer to review resource policies and identify risky permissions.

4. Monitor Cross-Account Sharing of Snapshots

   • Regularly review any shared snapshots using the describe-snapshots command to identify unexpected external shares. Configure alerts for any cross-account sharing of snapshots to quickly react to potential exfiltration attempts.

Cyngular Security's CIRA platform

Organizations can significantly enhance their cloud security posture by utilizing Cyngular Security's CIRA platform, with its advanced investigation and response capabilities, plays a critical role in ensuring that cloud environments remain secure against evolving threats.

The essence of cloud security lies in proactive measures, and Cyngular Security's CIRA platform incorporates this principle - automated, efficient cloud environment investigations. By integrating Cyngular Security's CIRA, you equip your team with the capability to quickly address and mitigate threats, ensuring robust protection for your cloud assets. Embrace Cyngular Security's CIRA for a deep, effective security strategy that keeps you ahead of threats.

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