Archived Content
In an effort to keep CISA.gov current, the archive contains outdated information that may not reflect current policy or programs.Network Time Protocol (NTP) Amplification Attacks
Last Revised
A vulnerability in the "monlist" feature of ntpd can allow remote attackers to cause distributed denial of service attack (DDoS) via forged requests. US-CERT and the Canadian Cyber Incident Response Center (CCIRC) have both observed active use of this attack vector in recent DDoS attacks.
US-CERT encourages users and administrators to review the CCIRC document as well as US-CERT Vulnerability Note VU#348126 for more information.
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