Minimizing Permissions for Cloud Forensics: A Practical Guide to Tightening Access in the Cloud

In the rapidly evolving landscape of cloud computing, organizations face a critical challenge: how to maintain tight security controls while ensuring the ability to conduct thorough forensic investigations when incidents occur.

The Dilemma: Balancing Access and Security

There is a tension between two crucial aspects of cloud security:

1. The need for Security Operations Center (SOC) and Incident Response (IR) teams to access comprehensive data for investigating and resolving security incidents.
2. The principle of least privilege and minimal manual access is advocated by cloud security best practices.

This conflict is particularly pronounced in modern cloud environments, where traditional physical access controls no longer apply, and infrastructure-as-code and containerization have transformed the landscape.

There are several common but less-than-ideal approaches to this challenge:

- Accepting limited data access, potentially leaving incidents unresolved

- Granting root-level access during major incidents, risking further compromise

- Relying on cloud or DevOps teams to retrieve data, causing delays and potential miscommunication

A Better Approach: Practical Strategies for Cloud Forensics

To address this challenge, it's crucial to implement strategies that strike a balance between necessary access and stringent security controls. Here are several key approaches:

1. Dedicated Forensics Accounts

Establishing a separate cloud account or subscription specifically for forensic activities is foundational. This approach isolates forensic activities from regular operations, preventing potential contamination from compromised environments. Dedicated accounts also enable tighter control over access policies, ensuring that forensic operations do not inadvertently expose sensitive data to unauthorized users.

A separate account allows for:

• Isolation: The forensic investigation environment is isolated from potentially compromised environments, reducing the risk of cross-contamination.
• Tighter Access Controls: Policies and controls can be more strictly enforced in a dedicated account, reducing the likelihood of unauthorized access.
• Simplified Governance: A clear and simplified chain of custody for digital evidence is easier to maintain, ensuring that forensic activities meet legal and regulatory requirements.

For more, see:

• https://aws.amazon.com/blogs/security/forensic-investigation-environment-strategies-in-the-aws-cloud/
• https://learn.microsoft.com/en-us/azure/architecture/example-scenario/forensics/
• https://cloud.google.com/blog/products/identity-security/how-to-use-live-forensics-to-analyze-a-cyberattack

2. Cross-Account Roles with Least Privilege

Using cross-account IAM roles, the forensics account can access other accounts, but only with permissions that are strictly necessary for the investigation. This ensures that the principle of least privilege is upheld, reducing the risk of unauthorized access or data exposure during the forensic process.

3. Temporary Credentials for Just-In-Time Access

Leveraging temporary credentials, such as AWS STS tokens, allows for just-in-time access during an investigation. These credentials are short-lived and scoped to specific resources, ensuring that access is granted only when absolutely necessary and is automatically revoked after the investigation is completed. This reduces the window of opportunity for potential attackers to exploit elevated permissions.

For more details for Google Cloud environments, see “Create short-lived credentials for a service account” and the request.time parameter.

For AWS, you can use commands such as:

aws sts get-session-token --duration-seconds 43200

aws sts assume-role --role-arn role-to-assume --role-session-name "sts-session-1" --duration-seconds 43200

For Azure, you can use commands such as:

az ad app credential reset --id <appId> --password <sp_password> --end-date 2024-01-01

4. Tag-Based Access Control

Pre-deploying access control based on resource tags is another effective strategy. By tagging resources with identifiers like "Forensics," access can be dynamically granted only to those resources that are relevant to the investigation. This targeted approach minimizes the risk of overexposure and ensures that forensic teams can quickly and efficiently access the data they need.

For example in Google Cloud:

expression: > resource.matchTag('tagKeys/ForensicsEnabled', '*')

For example in AWS:

Condition: StringLike: aws:ResourceTag/Name: ForensicsEnabled

Condition: StringLike: ssm:resourceTag/SSMEnabled: True

For example in Azure:

 "Condition": "StringLike(Resource[Microsoft.Resources/tags.example_key], '*')"

Challenges in Container Forensics

Containers present unique challenges for forensic investigations due to their ephemeral and dynamic nature. The orchestration and management of containers, whether on private clusters or using services like AWS EKS, introduce complexities in capturing and analyzing forensic data.

To effectively investigate containers, it's often necessary to acquire the underlying volume of a node or perform memory captures. However, these actions require specific IAM and network access to the node, as well as familiarity with the container environment, which may not always be straightforward.

Tighten Access, Enhance Security

The shift to cloud environments demands a rethinking of how we approach forensic investigations. By implementing strategies like dedicated forensic accounts, cross-account roles, temporary credentials, and tag-based access control, organizations can strike the right balance between access and security. These practices not only enhance the effectiveness of forensic investigations but also ensure that access is tightly controlled, reducing the risk of exacerbating an incident or compromising the investigation.

Ready to take control of your cloud forensic processes? Schedule a demo with Cado Security today and discover how our solutions can help you tighten access and secure your investigations in the cloud.