Timestamp sync verified with NTP to ±1s

Financial audit trails are only forensically reliable if the timestamps on every record can be trusted to reflect real wall-clock time. A server whose clock drifts 10 seconds from UTC produces log records that cannot be sequenced accurately against records from other systems — and sequence matters when reconstructing the order of events in a fraud investigation. NIST 800-53 AU-8 (Time Stamps) requires that information systems use internal system clocks to generate time stamps and synchronize with a defined authoritative time source. PCI-DSS 4.0 Req-10.6 requires that systems are configured to acquire the correct and consistent time and that time data is protected. NIST SP 800-92 recommends that log servers synchronize their clocks at least hourly via NTP. A ±1 second drift tolerance is the PCI DSS working standard.

Verify NTP is configured on every server that writes to the audit log, and add a drift-monitoring health check in your application:

# On a Linux host — verify in /etc/systemd/timesyncd.conf or /etc/ntp.conf
timedatectl status          # should show 'synchronized: yes'
timedatectl show-timesync  # should show NTPMessage with stratum <= 3

For containerized workloads, ensure the host NTP config is inherited. Add a drift check to your healthcheck endpoint in src/app/api/health/route.ts:

import { ntpClient } from 'ntp-time';

export async function GET() {
  const ntpTime = await ntpClient.syncTime();
  const drift = Math.abs(Date.now() - ntpTime.time.getTime());
  if (drift > 1000) {
    return Response.json({ status: 'degraded', clock_drift_ms: drift }, { status: 503 });
  }
  return Response.json({ status: 'ok', clock_drift_ms: drift });
}

If running on Vercel, AWS Lambda, or Cloudflare Workers, platform clock sync is managed for you — document this explicitly in docs/infrastructure.md so the skip criteria can be verified.