Policy manipulation

When a principal can write IAM policy, it can write itself to administrator. These are the most direct escalations in AWS: a single iam: write, no new resource, no host. They split into three shapes: changing which version of a managed policy is active, attaching a managed policy, and inlining a policy document.

Managed policy versions#

• CreatePolicyVersion: publish a new default version of a policy you can edit, granting full access.
• SetDefaultPolicyVersion: activate an existing, more permissive version.

Attaching managed policies#

• AttachUserPolicy: attach AdministratorAccess to a user you control.
• AttachGroupPolicy: attach a privileged policy to a group you belong to.
• AttachRolePolicy: attach a privileged policy to a role you can assume.

Inlining policy documents#

• PutUserPolicy: inline an allow-all document onto a user.
• PutGroupPolicy: inline an allow-all document onto a group.
• PutRolePolicy: inline an allow-all document onto a role.

References#

• Rhino Security Labs: AWS privilege escalation (policy paths)
• BishopFox: iam-vulnerable
• Pacu (Rhino Security Labs)
• Hacking the Cloud: AWS