Agent Dart is missing certificate verification checks
Date: 2024-10
Affected: pub/agent_dart
Attack vector: other
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2024-48915
CWE: CWE-295
CWE-347
CVSS:  (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N)

Certificate verification (in [lib/agent/certificate.dart](https://github.com/AstroxNetwork/agent_dart/blob/main/lib/agent/certificate.dart)) has been found to contain two issues: - During the delegation verification (in [_checkDelegation](https://github.com/AstroxNetwork/agent_dart/blob/f50971dfae3f536c1720f0084f28afbcf5d99cb5/lib/agent/certificate.dart#L162) function) the canister_ranges aren't verified. The impact of not checking the canister_ranges is that a subnet can sign canister responses in behalf of another subnet. You have more details in the IC specification [here](https://internetcomputer.org/docs/current/references/ic-interface-spec#certification-delegation). Also for reference you can check how is this implemented in [the agent-rs](https://github.com/dfinity/agent-rs/blob/608a3f4cfdcdfc5ca1ca74a1b9d33f2137a2d324/ic-agent/src/agent/mod.rs#L903-L914). - The certificate’s timestamp, i.e /time path, is not verified, meaning that the certificate effectively has no expiration time. The [IC spec](https://internetcomputer.org/docs/current/references/ic-interface-spec#http-query) doesn’t specify an expiry times, it gives some suggestions, quoting: "A reasonable expiry time for timestamps in R.signatures and the certificate Cert is 5 minutes (analogously to the maximum allowed ingress expiry enforced by the IC mainnet). Delegations require expiry times of at least a week since the IC mainnet refreshes the delegations only after replica upgrades which typically happ


Mitigations:

Architectural layers (MAESTRO):