r1 - 2015-10-23 - 09:23:30 - HarlanStennYou are here: NTP >  Main Web > SecurityNotice > NtpBug2919
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 2919

TALOS-CAN-0063: ntpq atoascii() potential memory corruption

  • Date Resolved: Stable (4.2.8p4) 21 Oct 2015
  • References: Sec 2919 / CVE-2015-7852
  • Affects: All ntp-4 releases running up to, but not including 4.2.8p4, and 4.3.0 up to, but not including 4.3.77
  • CVSS: (AV:N/AC:H/Au:N/C:N/I:P/A:P) Base Score: 4.0, worst case
  • Summary: If an attacker can figure out the precise moment that ntpq is listening for data and the port number it is listening on or if the attacker can provide a malicious instance ntpd that victims will connect to then an attacker can send a set of crafted mode 6 response packets that, if received by ntpq, can cause ntpq to crash.
  • Mitigation:
    • Implement BCP-38.
    • Upgrade to 4.2.8p4, or later, from the NTP Project Download Page or the NTP Public Services Project Download Page.
    • If you are unable to upgrade and you run ntpq against a server and ntpq crashes, try again using raw mode. Build or get a patched ntpq and see if that fixes the problem. Report new bugs in ntpq or abusive servers appropriately.
    • If you use ntpq in scripts, make sure ntpq does what you expect in your scripts.
  • Credit: This weakness was discovered by Yves Younan and Aleksander Nikolich of Cisco Talos.
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