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العربيةAttach an instance profile, then read its credentials
Can attach a role's instance profile to an EC2 instance and steal its credentials via IMDS.
Grants escalation only in combination. All of these are needed together:
iam:PassRoleec2:AssociateIamInstanceProfileiam:PassRole can attach a role's instance profile to an EC2 instance and steal its credentials via IMDS, but only when it is held together with ec2:AssociateIamInstanceProfile. Held together they reach administrator access.
Why it is dangerous
A principal holds iam:PassRole on the target role together with ec2:AssociateIamInstanceProfile, so it can attach the target role's instance profile to an EC2 instance it controls and then read the role's temporary credentials from IMDS. Unlike ec2:RunInstances a needs no new instance: it re-points an existing box at a more privileged role, which is quieter and cheaper.
In MITRE ATT&CK terms this maps to T1552.005, Unsecured Credentials: Cloud Instance Metadata API, under the privilege escalation tactic. AWS records it in CloudTrail as AssociateIamInstanceProfile, ReplaceIamInstanceProfileAssociation. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
Detection
AssociateIamInstanceProfileReplaceIamInstanceProfileAssociationPrerequisites
An EC2 instance the attacker controls or can reach, plus IMDS access on it. The role must be in an instance profile.
Tactic
Privilege Escalation
A control that would remove it: Remove iam:PassRole for this role or scope it with iam:PassedToService; restrict ec2:AssociateIamInstanceProfile / ReplaceIamInstanceProfileAssociation.
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 attach a role's instance profile to an EC2 instance and steal its credentials via IMDS.
What else is needed for iam:PassRole to be dangerous?
It becomes an escalation only when held together with ec2:AssociateIamInstanceProfile. On its own it is not enough, which is what makes the combination easy to miss.
How is attach an instance profile, then read its credentials detected?
Watch for AssociateIamInstanceProfile, ReplaceIamInstanceProfileAssociation in CloudTrail. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
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; restrict ec2:AssociateIamInstanceProfile / ReplaceIamInstanceProfileAssociation. 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?
T1552.005, Unsecured Credentials: Cloud Instance Metadata API, under the privilege escalation tactic.
Related paths
References
Find this in your own account
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