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العربيةDecrypt with KMS key
Can decrypt ciphertext protected by a KMS key.
Grants escalation on its own.
kms:DecryptOn its own, kms:Decrypt can decrypt ciphertext protected by a KMS key. On a wide resource scope that alone reaches the data itself.
Why it is dangerous
A principal can call kms:Decrypt with the key, verified against both the principal's identity policy and the key's key policy. The key is a gatekeeper: decrypt access unlocks every ciphertext the key protects (encrypted secrets, volumes, snapshots, S3 objects), so control of the key amplifies into control of all the data it gates.
In MITRE ATT&CK terms this maps to T1552, Unsecured Credentials, under the credential access tactic. AWS records it in CloudTrail as Decrypt. The call is quiet against normal activity, so it is easy to miss without a rule for it.
Detection
DecryptPrerequisites
kms:Decrypt on the key (from identity OR the key policy) plus possession of (or access to) the ciphertext.
MITRE ATT&CK
T1552 · Unsecured CredentialsTactic
Credential Access
A control that would remove it: Tighten the KMS key policy and the principal's kms:Decrypt; use grants/least-privilege key policies.
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 kms:Decrypt allow?
Can decrypt ciphertext protected by a KMS key.
Can kms:Decrypt escalate privileges on its own?
Yes. Held on a broad enough resource it reaches the data itself with no other permission.
How is decrypt with KMS key detected?
Watch for Decrypt 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: Tighten the KMS key policy and the principal's kms:Decrypt; use grants/least-privilege key policies. 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?
T1552, Unsecured Credentials, under the credential access tactic.
Related paths
References
Find this in your own account
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