r2 - 2016-04-27 - 01:10:04 - SueGravesYou are here: NTP >  Main Web > SecurityNotice > NtpBug2948
NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to being used in distributed denial-of-service (DDoS) attacks. Please also take this opportunity to defeat denial-of-service attacks by implementing Ingress and Egress filtering through BCP38.

ntp-4.2.8p15 was released on 23 June 2020. It addresses 1 medium-severity security issue in ntpd, and provides 13 non-security bugfixes over 4.2.8p13.

Please see the NTP Security Notice for vulnerability and mitigation details.

Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.

NTP Bug 2948

Potential Infinite Loop in ntpq

  • Date Resolved: Stable (4.2.8p6) 19 Jan 2016; Dev (4.3.90) 19 Jan 2016
  • References: Sec 2548 / CVE-2015-8158
  • Affects: All ntp-4 releases up to, but not including 4.2.8p6, and 4.3.0 up to, but not including 4.3.90
  • CVSS2: (AV:N/AC:M/Au:N/C:N/I:N/A:P) Base Score: 4.3 - MEDIUM
  • CVSS3: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N) Base Score: 5.3 - MEDIUM
  • Summary: ntpq processes incoming packets in a loop in getresponse(). The loop's only stopping conditions are receiving a complete and correct response or hitting a small number of error conditions. If the packet contains incorrect values that don't trigger one of the error conditions, the loop continues to receive new packets. Note well, this is an attack against an instance of ntpq, not ntpd, and this attack requires the attacker to do one of the following:
    • Own a malicious NTP server that the client trusts
    • Prevent a legitimate NTP server from sending packets to the ntpq client
    • MITM the ntpq communications between the ntpq client and the NTP server
  • Mitigation:
  • Credit: This weakness was discovered by Jonathan Gardner of Cisco ASIG.
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