Information
AWS CloudShell is a convenient way of running CLI commands against AWS services; a managed IAM policy ('AWSCloudShellFullAccess') provides full access to CloudShell, which allows file upload and download capability between a user's local system and the CloudShell environment. Within the CloudShell environment, a user has sudo permissions and can access the internet. Therefore, it is feasible to install file transfer software, for example, and move data from CloudShell to external internet servers.
Access to this policy should be restricted, as it presents a potential channel for data exfiltration by malicious cloud admins who are given full permissions to the service. AWS documentation describes how to create a more restrictive IAM policy that denies file transfer permissions.
NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
Solution
From Console
- Open the IAM console at
https://console.aws.amazon.com/iam/
- In the left pane, select Policies
- Search for and select AWSCloudShellFullAccess
- On the Entities attached tab, for each item, check the box and select Detach