Configuring Regular Expression to Extract Policy Username

Extract the policy username from the AWS identity.

Configuring Regular Expression to Extract Policy Username

Cloud Protect Lambda Function exposes USERNAME_REGEX configuration to allow extraction of policy username from user in the request.

  • USERNAME_REGEX Lambda Environment configuration

    The USERNAME_REGEX configuration can be used to extract policy username from user in the request. The following are allowed values for USERNAME_REGEX:

    • 1 - Default build-in regular expression is used:

      ^arn:aws:(?:iam|sts)::[0-9]{12}:(?:role|user|group|assumed\-role|federated\-user)\/([\w\/+=,.\-]{1,1024}|[\w\/+=,.\-@]{1,1024})(?:@[a-zA-Z0-9\-]{1,320}(?:\.\w+)+)?$
      
    • ^User regex$ - Custom regex with one capturing group. This group is used to extract the username. Examples below show different regular expression values and the resulting policy user.

USERNAME_REGEX

User in the request

Effective Policy User

Not Set

arn:aws:iam::123456789012:user/juliet.snow

arn:aws:iam::123456789012:user/juliet.snow

arn:aws:sts::123456789012:assumed-role/TestSaml

arn:aws:sts::123456789012:assumed-role/TestSaml

1

arn:aws:iam::123456789012:user/juliet.snow

juliet.snow

arn:aws:sts::123456789012:assumed-role/TestSaml

TestSaml

^arn:aws:(?:iam|sts)::[0-9]{12}:((?:role|user|group|assumed-role|federated-user).*)$

arn:aws:iam::123456789012:user/juliet.snow

user/juliet.snow

arn:aws:sts::123456789012:assumed-role/TestSaml

assumed-role/TestSaml


Last modified : November 27, 2025