The sync endpoint in YubiKey Validation Server before 2.40 allows remote attackers to replay an OTP. NOTE: this issue is potentially relevant to persons outside Yubico who operate a self-hosted OTP validation service with a non-default configuration such as an open sync pool; the issue does NOT affect YubiCloud.
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Yubikey_one_time_password_validation_server | Yubico | * | 2.40 (excluding) |
| Yubikey-val | Ubuntu | bionic | * |
| Yubikey-val | Ubuntu | trusty | * |
| Yubikey-val | Ubuntu | xenial | * |