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العربيةPass role to CodeBuild
Can create a CodeBuild project with a role and run shell commands as it.
Grants escalation only in combination. All of these are needed together:
iam:PassRolecodebuild:CreateProjectcodebuild:StartBuildiam:PassRole can create a CodeBuild project with a role and run shell commands as it, but only when it is held together with codebuild:CreateProject, codebuild:StartBuild. Held together they reach administrator access.
Why it is dangerous
A principal holds iam:PassRole on the target role plus codebuild:CreateProject and codebuild:StartBuild, so it can define a build project whose buildspec runs arbitrary shell commands with the target role as the service role, then start the build, the commands execute with the target role's permissions and can exfiltrate its credentials. Because the target role trusts codebuild.amazonaws.com the pass is accepted; the privileged role is full privilege escalation.
In MITRE ATT&CK terms this maps to T1648, Serverless Execution, under the privilege escalation tactic. AWS records it in CloudTrail as CreateProject, StartBuild. The call is loud in CloudTrail and stands out from normal activity.
Detection
CreateProjectStartBuildPrerequisites
Target role's trust policy must allow codebuild.amazonaws.com.
MITRE ATT&CK
T1648 · Serverless ExecutionTactic
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 create a CodeBuild project with a role and run shell commands as it.
What else is needed for iam:PassRole to be dangerous?
It becomes an escalation only when held together with codebuild:CreateProject, codebuild:StartBuild. On its own it is not enough, which is what makes the combination easy to miss.
How is pass role to CodeBuild detected?
Watch for CreateProject, StartBuild 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?
T1648, Serverless Execution, 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.