NFD

CommandAuthenticator design is subject to a form of denial-of-service attack.

Steps to reproduce:

1. Generate signing certificate A.ndncert, whose private key is accessible by appA only.
2. In NFD configuration file, grant a privilege to A.ndncert.
3. From appB, send a control command of the granted privilege with current timestamp, a KeyLocator corresponding to A.ndncert, and a bogus signature. The authenticator will reject this control command due to invalid signature, but the ndn::security::CommandInterestValidator will internally record the timestamp.
4. From appB, send another control command of the granted privilege with current timestamp plus one day, a KeyLocator corresponding to A.ndncert, and a bogus signature. The authenticator will reject this control command due to invalid signature, but the ndn::security::CommandInterestValidator will internally bump the last timestamp of A.ndncert's key name by one day.
5. From appA, send a control command of the granted privilege with current timestamp, and correct KeyLocator and signature corresponding to A.ndncert.

Expected: The command from appA is accepted.
Actual: The command from appA is rejected due to backdated timestamp.