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العربيةGrant bucket read via ACL
Can rewrite a bucket's ACL to grant public or attacker read.
Grants escalation on its own.
s3:PutBucketAclOn its own, s3:PutBucketAcl can rewrite a bucket's ACL to grant public or attacker read. On a wide resource scope that alone reaches access for an outside or public principal.
Why it is dangerous
A principal can call s3:PutBucketAcl on the bucket to grant READ to AllUsers, AuthenticatedUsers, or an external canonical id, then read the objects. An alternate exposure path to the bucket-policy grant.
In MITRE ATT&CK terms this maps to T1530, Data from Cloud Storage, under the collection tactic. AWS records it in CloudTrail as PutBucketAcl. The call is quiet against normal activity, so it is easy to miss without a rule for it. It also gives an attacker a way to keep access after the first foothold is closed, so it is worth watching even when it looks like routine administration.
Detection
PutBucketAclPrerequisites
s3:PutBucketAcl on the bucket; ACLs enabled; Block Public Access permits the grant.
MITRE ATT&CK
T1530 · Data from Cloud StorageTactic
Collection
A control that would remove it: Remove s3:PutBucketAcl from the principal; enforce Object Ownership = BucketOwnerEnforced (disables ACLs) and Block Public Access.
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 s3:PutBucketAcl allow?
Can rewrite a bucket's ACL to grant public or attacker read.
Can s3:PutBucketAcl 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 grant bucket read via ACL detected?
Watch for PutBucketAcl in CloudTrail. The call is quiet against normal activity, so it is easy to miss without a rule for it.
How do you break this path?
A control that would remove it is: Remove s3:PutBucketAcl from the principal; enforce Object Ownership = BucketOwnerEnforced (disables ACLs) and Block Public Access. 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?
T1530, Data from Cloud Storage, under the collection 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.