CVE-2021-46873: 
WireGuard vulnerability analysis and mitigation

WireGuard 0.5.3 on Windows contains a security vulnerability where the software does not properly handle scenarios where an adversary might manipulate a victim's system time to a future value, particularly when unauthenticated NTP is used (NVD, WireGuard List). This vulnerability was disclosed in January 2023.

The vulnerability stems from WireGuard's use of timestamps for preventing replay attacks in NoiseIK 1-RTT protocol. The system relies on responders rejecting packets with timestamps larger than the last one received. When an attacker manipulates the system time to a future value and causes the victim to send an initiation message, it can result in the timestamp being set to a maximum value that can be replayed indefinitely (WireGuard List). The vulnerability has been assigned a CVSS v3.1 Base Score of 5.3 MEDIUM (Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) (NVD).

The primary impact of this vulnerability is that an attacker can render a victim's static private key permanently unusable. When the attacker successfully sets the system time to a future value and causes the initiation message to be sent, that future timestamp can always be replayed, effectively making the key unusable for future connections (WireGuard List).

Several potential mitigations have been discussed, including: using authenticated alternatives to NTP, implementing battery-powered RTCs, storing monotonic counters on disk, maintaining boot-time timestamps, disabling large time jumps in NTP, and requiring synchronized clocks for responders (WireGuard List).