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العربيةHijack App Runner service role
Can reconfigure an App Runner service to run attacker code as its instance role.
Grants escalation on its own.
apprunner:UpdateServiceOn its own, apprunner:UpdateService can reconfigure an App Runner service to run attacker code as its instance role. On a wide resource scope that alone reaches administrator access.
Why it is dangerous
A principal can call apprunner:UpdateService on an existing App Runner service that already carries the instance role, reconfiguring it to run attacker-controlled code, a malicious StartCommand, a container image with a web shell, or a repository with a malicious apprunner.yaml. On the next deployment App Runner runs that code as the target role, no iam:PassRole and no apprunner:CreateService needed, because the target role is already bound to the service. The code reads the target role's live credentials from the runtime environment or calls AWS directly; if the target role is privileged this is full privilege escalation against a service that was already trusted.
In MITRE ATT&CK terms this maps to T1578, Modify Cloud Compute Infrastructure, under the privilege escalation tactic. AWS records it in CloudTrail as UpdateService. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
Detection
UpdateServicePrerequisites
An existing App Runner service with an instance role attached; permission to update it. Source/image config changes must be permitted (the default).
MITRE ATT&CK
T1578 · Modify Cloud Compute InfrastructureTactic
Privilege Escalation
A control that would remove it: Restrict apprunner:UpdateService on services that carry a privileged instance role; review source/image config changes.
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 apprunner:UpdateService allow?
Can reconfigure an App Runner service to run attacker code as its instance role.
Can apprunner:UpdateService escalate privileges on its own?
Yes. Held on a broad enough resource it reaches administrator access with no other permission.
How is hijack App Runner service role detected?
Watch for UpdateService 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: Restrict apprunner:UpdateService on services that carry a privileged instance role; review source/image config changes. 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, Modify Cloud Compute Infrastructure, under the privilege escalation tactic.
Related paths
References
Find this in your own account
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