Findings

CVE-2024-48915

Agent Dart is missing certificate verification checks

Published Oct 15, 2024 · updated Oct 15, 2024

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 happen once a week". For reference you can check how is this implemented in the agent-rs ([here](https://github.com/dfinity/agent-rs/blob/608a3f4cfdcdfc5ca1ca74a1b9d33f2137a2d324/ic-agent/src/agent/mod.rs#L820) and [here](https://github.com/dfinity/agent-rs/blob/608a3f4cfdcdfc5ca1ca74a1b9d33f2137a2d324/ic-agent/src/agent/mod.rs#L876-L887)). **Additionally**, seems [replica signed queries](https://internetcomputer.org/blog/features/replica-signed-queries) aren’t implemented