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العربيةSelf-grant Lambda invoke via resource policy
Can add itself to a function's invoke policy and trigger it (runs as the exec role).
Grants escalation on its own.
lambda:AddPermissionOn its own, lambda:AddPermission can add itself to a function's invoke policy and trigger it (runs as the exec role). On a wide resource scope that alone reaches access for an outside or public principal.
Why it is dangerous
A principal can call lambda:AddPermission on a privileged function to add itself (or an external account) to the function's invoke policy, then trigger it. The function executes as its the execution role, so invoking it is code execution as that role - the prize is not the function but the role it surrenders and everything that role can reach. The attacker rewrites the invoke lock rather than holding an existing invoke grant.
In MITRE ATT&CK terms this maps to T1098, Account Manipulation, under the privilege escalation tactic. AWS records it in CloudTrail as AddPermission. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
Detection
AddPermissionPrerequisites
lambda:AddPermission on the function. The abuse additionally assumes no SCP/boundary/PrincipalOrgID guardrail blocks the over-grant, AND that invoking the function actually surrenders the execution role (attacker-influenced code, or the function leaks creds/output) - a plain invoke of trusted code does not.
MITRE ATT&CK
T1098 · Account ManipulationTactic
Privilege Escalation
A control that would remove it: Restrict lambda:AddPermission to function owners; deny invoke-policy writes via SCP; require aws:PrincipalOrgID / SourceArn on function resource policies; least-privilege the execution role.
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 lambda:AddPermission allow?
Can add itself to a function's invoke policy and trigger it (runs as the exec role).
Can lambda:AddPermission escalate privileges on its own?
Yes. Held on a broad enough resource it reaches access for an outside or public principal with no other permission.
How is self-grant Lambda invoke via resource policy detected?
Watch for AddPermission 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 lambda:AddPermission to function owners; deny invoke-policy writes via SCP; require aws:PrincipalOrgID / SourceArn on function resource policies; least-privilege the execution role. 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?
T1098, Account Manipulation, under the privilege escalation tactic.
Related paths
References
Find this in your own account
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