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العربيةPass role to GameLift fleet
Can launch a GameLift fleet with a role and run a server process as it.
Grants escalation only in combination. All of these are needed together:
iam:PassRolegamelift:CreateBuildgamelift:CreateFleetiam:PassRole can launch a GameLift fleet with a role and run a server process as it, but only when it is held together with gamelift:CreateBuild, gamelift:CreateFleet. Held together they reach administrator access.
Why it is dangerous
A principal holds iam:PassRole on the target role plus gamelift:CreateBuild and gamelift:CreateFleet, so it can upload an attacker-controlled game-server build and launch a fleet with the target role as its EC2 instance role, the server process runs on the fleet's EC2 with the target role's permissions and reads the target role's credentials from the instance credential provider. Because the target role trusts ec2.amazonaws.com the pass is accepted; if the target role is privileged this is full privilege escalation.
In MITRE ATT&CK terms this maps to T1578.002, Modify Cloud Compute Infrastructure: Create Cloud Instance, under the privilege escalation tactic. AWS records it in CloudTrail as CreateBuild, CreateFleet. The call is loud in CloudTrail and stands out from normal activity.
Detection
CreateBuildCreateFleetPrerequisites
Target role must be usable as a GameLift fleet EC2 instance role and trust ec2.amazonaws.com.
Tactic
Privilege Escalation
A control that would remove it: Remove iam:PassRole for this role or scope it with iam:PassedToService.
Whether to apply it depends on how the permission is used in your environment, so it is a business decision rather than an automatic fix. The same permission can be load-bearing in one account and pure risk in another.
Pathbreak confirms whether this path resolves in your account, ranks it against the others by how much it opens up, and uses your threat model and business context to show which paths are worth cutting.
Questions
What does iam:PassRole allow?
Can launch a GameLift fleet with a role and run a server process as it.
What else is needed for iam:PassRole to be dangerous?
It becomes an escalation only when held together with gamelift:CreateBuild, gamelift:CreateFleet. On its own it is not enough, which is what makes the combination easy to miss.
How is pass role to GameLift fleet detected?
Watch for CreateBuild, CreateFleet in CloudTrail. The call is loud in CloudTrail and stands out from normal activity.
How do you break this path?
A control that would remove it is: Remove iam:PassRole for this role or scope it with iam:PassedToService. Whether to apply it depends on how the permission is used in your account, so it is a business decision rather than an automatic fix.
Which MITRE ATT&CK technique is this?
T1578.002, Modify Cloud Compute Infrastructure: Create Cloud Instance, under the privilege escalation tactic.
Related paths
References
Find this in your own account
We run a read-only scan of one AWS account and show you which of these paths exist, ranked by blast radius, with the change that breaks each one. First validated paths within the hour.