NTP BUG 3082: read_mru_list() does inadequate incoming packet checks

Last update: June 27, 2022 20:45 UTC (51d68a4aa)

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Summary

Resolved	4.2.8p9	21 Nov 2016
References	Bug 3082	CVE-2016-7434
Affects	ntp-4.2.7p22, up to but not including ntp-4.2.8p9, and ntp-4.3.0 up to, but not including ntp-4.3.94.	Resolved in 4.2.8p9.
CVSS2 Score	LOW 3.8	AV:L/AC:H/Au:S/C:N/I:N/A:C
CVSS3 Score	LOW 3.8	CVSS:3.0/AV:P/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

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Description

If ntpd is configured to allow mrulist query requests from a server that sends a crafted malicious packet, ntpd will crash on receipt of that crafted malicious mrulist query packet.

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Mitigation

• Only allow mrulist query packets from trusted hosts.
• Implement BCP-38.
• Upgrade to 4.2.8p9 or later.
• Properly monitor your ntpd instances, and auto-restart ntpd (without -g) if it stops running.

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Credit

This weakness was discovered by Magnus Stubman.

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Timeline

• 2016 Nov 21: Public release
• 2016 Nov 15: CERT given our software release notification
• 2016 Nov 14: Early Access Program Release: Premier and Partner Institutional Members
• : Notification to Institutional Members
• : Report received