AWS SDK for .NET Region Parameter Validation Vulnerability

A vulnerability exists in the AWS SDK for .NET, specifically in version 4.0.0 prior to 4.0.3.3. This issue allows customer applications to improperly route AWS API calls to non-existent or non-AWS hosts by exploiting invalid region values. An actor with access to the SDK environment could manipulate the region input to an incorrect value, leading to misrouted API calls. Although the SDK operated within the shared responsibility model's safety requirements, this vulnerability highlighted the need for additional safeguards in customer implementations.

Impact

Exploitation of this vulnerability could cause AWS API calls to be directed to incorrect hosts, potentially disrupting service or causing unexpected behavior in applications.

Remediation

Users are advised to update to version 4.0.3.3 or later, and to follow AWS security best practices for SDK configuration. Regularly updating the AWS SDK for .NET to the latest release is also recommended.