What’s Vulnerable › Vulnerabilities

CVE-2015-7973

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2017-01-30 · updated 2026-06-17
• Weakness: CWE-254

Description

NTP before 4.2.8p6 and 4.3.x before 4.3.90, when configured in broadcast mode, allows man-in-the-middle attackers to conduct replay attacks by sniffing the network.

Affected products

• Canonical Ubuntu Linux: 12.04, 14.04, 16.04
• FreeBSD: from 10.0 before 10.1; 9.3, 9.3-p1, 9.3-p10, 9.3-p12, 9.3-p13, 9.3-p16 (+44) — fixed in 10.1
• Clustered Data ONTAP: all versions
• NetApp Oncommand Balance: all versions
• NTP: before 4.2.8; from 4.3.0 before 4.3.90; 4.2.8, 4.2.8-p1, 4.2.8-p1-beta1, 4.2.8-p1-beta2, 4.2.8-p1-beta3, 4.2.8-p1-beta4 (+13) — fixed in 4.2.8, 4.3.90
• Siemens Tim 4R-Ie Dnp3 Firmware: all versions
• Siemens Tim 4R-Ie Firmware: all versions

How to fix

Upgrade to a fixed version: FreeBSD 10.1; NTP 4.2.8, 4.3.90. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00059.html
• http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00060.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00020.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00038.html
• http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html
• http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
• http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
• http://lists.opensuse.org/opensuse-updates/2016-05/msg00114.html
• http://support.ntp.org/bin/view/Main/NtpBug2935
• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160127-ntpd
• http://www.securityfocus.com/bid/81963
• http://www.securitytracker.com/id/1034782

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