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-4.2.8p10 was released on 21 March 2017. It addresses 6 medium- and 5 low-severity security issues, 4 informational security topics, 15 bugfixes, and contains other improvements over 4.2.8p9.

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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