NTP BUG 2918: Potential path traversal vulnerability in the config file saving of ntpd on VMS

Last update: June 28, 2022 20:06 UTC (57417e17c)

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Summary

Resolved	4.2.8p4	21 Oct 2015
References	Bug 2918	CVE-2015-7851
Affects	All ntp-4 releases running under VMS up to, but not including 4.2.8p4, and 4.3.0 up to, but not including 4.3.77.	Resolved in 4.2.8p4.
CVSS2 Score	5.2, worst case	AV:N/AC:H/Au:M/C:N/I:P/A:C

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Description

If ntpd is configured to allow remote configuration, and if the (possibly spoofed) IP address is allowed to send remote configuration requests, and if the attacker knows the remote configuration password or if ntpd was configured to disable authentication, then an attacker can send a set of packets to ntpd that may cause ntpd to overwrite files.

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Mitigation

• Implement BCP-38.
• Upgrade to 4.2.8p4 or later.
• If you are unable to upgrade, remote configuration of NTF’s ntpd requires:
  • an explicitly configured “trusted” key. Only configure this if you need it.
  • access from permitted IP addresses. You choose the IPs.
  • authentication. Don’t disable it. Practice key security safety.
• If you use ntpq in scripts, make sure ntpq does what you expect in your scripts.

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Credit

This weakness was discovered by Yves Younan of Cisco Talos.

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Timeline

• 2015 Oct 21: Public release
• 2015 Oct 6: Early Access Program Release: Premier and Partner Institutional Members
• 2015 Aug 26: Notification to Institutional Members for 1593, 1774, 2382, 2899, and 2902
• 2015 Aug 20: Initial notification of 2902; analysis begins
• 2015 Aug 11: Initial notification of 2899; analysis begins