PT-2016-4855 · Ntpsec+8 · Ntpsec+8

Matthew Van Gundy + 1 · Published 2016-04-28 · Updated 2025-04-20 · CVE-2016-1547

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Name of the Vulnerable Software and Affected Versions NTP versions 4.2.8p4 and earlier NTPSec version a5fb34b9cc89b92a8fef2f459004865c93bb7f92

Description An off-path attacker can cause a preemptible client association to be demobilized by sending a crypto NAK packet to a victim client with a spoofed source address of an existing associated peer. This issue persists even when authentication is enabled.

Recommendations For NTP versions 4.2.8p4 and earlier, consider disabling the preemptible client association feature until a patch is available. For NTPSec version a5fb34b9cc89b92a8fef2f459004865c93bb7f92, restrict access to the crypto NAK packet handling mechanism to minimize the risk of exploitation. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

RCE

Weakness Enumeration

CWE-20

Related Identifiers

ALT-PU-2017-2335

CESA-2016_1141

CVE-2016-1547

DLA-559-1

DSA-3629-1

FREEBSD-SA-16_16

OPENSUSE-SU-2016_1329-1

OPENSUSE-SU-2024:10181-1

RHSA-2016:1141

RHSA-2016:1552

RHSA-2016_1141

SUSE-SU-2016:1278-1

SUSE-SU-2016:1291-1

SUSE-SU-2016:1471-1

SUSE-SU-2016:1568-1

USN-3096-1

Affected Products

Alt Linux

Centos

Cisco Ios Xr

Freebsd

Ntp

Ntpsec

Red Hat

Suse

Ubuntu

References · 134

• https://security.freebsd.org/advisories/FreeBSD-SA-16:16.ntp.asc · Vendor Advisory
• https://security.gentoo.org/glsa/201607-15 · Vendor Advisory
• https://ubuntu.com/security/CVE-2016-1550 · Vendor Advisory
• https://ubuntu.com/security/CVE-2015-7976 · Vendor Advisory
• http://debian.org/security/2016/dsa-3629 · Vendor Advisory
• http://rhn.redhat.com/errata/RHSA-2016-1552.html · Vendor Advisory
• https://osv.dev/vulnerability/USN-3096-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2016-2516 · Vendor Advisory
• https://ubuntu.com/security/CVE-2016-4954 · Vendor Advisory
• https://ubuntu.com/security/CVE-2016-4955 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2016-1547 · Vendor Advisory
• https://ubuntu.com/security/CVE-2015-7977 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2016-1547 · Security Note
• https://access.redhat.com/errata/RHSA-2016:1141 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2016:1278-1 · Vendor Advisory