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العربيةPublic Lambda function URL
A Lambda has a function URL with auth type NONE (public)..
No IAM permission is needed. The exposure is in the resource's own configuration, so anyone the policy names, or everyone when it is public, can reach it.
This is a configuration exposure, not a permission. A Lambda has a function URL with auth type NONE (public). Anyone the policy allows, or everyone when it is public, can reach it with no IAM access of their own.
Why it is dangerous
This Lambda exposes an unauthenticated function URL; anyone on the internet can invoke it and it runs with the function's execution role.
In MITRE ATT&CK terms this maps to T1190, Exploit Public-Facing Application, under the initial access tactic.
Detection
Prerequisites
None beyond holding the permission.
MITRE ATT&CK
T1190 · Exploit Public-Facing ApplicationTactic
Initial Access
A control that would remove it: Delete the public function URL or set its auth type to AWS_IAM.
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 this configuration allow?
A Lambda has a function URL with auth type NONE (public).
Does this need any IAM permission?
No. It is a configuration exposure. Anyone the resource policy names, or everyone when it is public, can reach it without holding any permission of their own.
How is public Lambda function URL detected?
Watch for the related CloudTrail management events.
How do you break this path?
A control that would remove it is: Delete the public function URL or set its auth type to AWS_IAM. 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?
T1190, Exploit Public-Facing Application, under the initial access tactic.
Related paths
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.