The US is almost the only country that doesn't fully fund Network Time Protocol (NTP), which the Network Time Foundation keeps.
If NTF doesn't stay funded and starts having to shut down, this would cause interruptions in banking, airline, stock market, and any business that relies on accurate time, including the Internet itself and all the ISPs out there.
1. Time Synchronization: NTP is responsible for synchronizing the time across networked devices. If compromised, accurate timekeeping would fail, leading to discrepancies in logs, authentication tokens, and other time-dependent processes.
2. Security Certificates: SSL/TLS certificates rely on accurate time synchronization. A compromised NTP could cause certificate validation failures, potentially allowing attackers to impersonate legitimate services.
3. Authentication Tokens: Time-based authentication tokens (like TOTP or HOTP) would become unreliable. Users might be locked out of systems due to token expiration issues.
4. Cryptographic Protocols: Many cryptographic protocols depend on precise timing. A compromised NTP could disrupt cryptographic operations, affecting secure communication channels.
5. Log Integrity: System logs, audit trails, and event timestamps would lose integrity. This could hinder forensic investigations and make it harder to detect security incidents.
6. Kerberos Authentication: Kerberos relies on synchronized clocks for authentication. A compromised NTP would disrupt Kerberos ticket issuance and validation.
7. Network Access Control: Network Access Control (NAC) systems use time-based policies. A compromised NTP could lead to incorrect access decisions, allowing unauthorized devices onto the network.
8. Backup and Replication: Backup schedules and data replication rely on accurate time. A compromised NTP might cause backups to fail or lead to data loss during replication.
9. Financial Transactions: Financial systems use precise timestamps for transaction processing. A compromised NTP could disrupt stock exchanges, banking, and other financial services.
10. IoT Devices: Many Internet of Things (IoT) devices synchronize time using NTP. A mass compromise could affect smart homes, industrial automation, and critical infrastructure.
As you can see, should NTP become wildlt compromised it would have far-reaching implications, impacting security, reliability, and functionality across various domains. For these reasons, it is vital that the latest version of NTP is being ran on servers around the world.
Learn more by visiting https://nwtime.org

The US has its own system. It is the joint responsibility of the Secretary of Commerce and the Secretary of the Navy. The Secretary of Commerce delegates the timekeeping responsibility to the National Institute of Standards and Technology (NIST, an agency of the Department of Commerce), and the Secretary of the Navy delegates the timekeeping responsibility to the United States Naval Observatory (USNO) in the Department of Defense (DoD). UTC, UTC(NIST) and UTC(USNO) are equivalent at the 20 nanosecond level of accuracy.