Denial of service in NTP

1) Race condition

EUVDB-ID: #VU54026

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-4955

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a race condition in ntpd. A remote attacker can exploit the race and cause a denial of service condition on the target system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ntp: 4.0.72 - 4.2.8p4-RC1

CPE2.3

• cpe:2.3:a:ntp_org:ntp:4.0.72:*:*:*:*:*:*:*
• cpe:2.3:a:ntp_org:ntp:4.0.73:*:*:*:*:*:*:*
• cpe:2.3:a:ntp_org:ntp:4.0.90:*:*:*:*:*:*:*

External links

https://www.kb.cert.org/vuls/id/321640
https://support.ntp.org/bin/view/Main/NtpBug3043
https://bugs.ntp.org/3043
https://support.ntp.org/bin/view/Main/SecurityNotice
https://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.html
https://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.html
https://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.html
https://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.html
https://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.html
https://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
https://www.securityfocus.com/bid/91007
https://security.gentoo.org/glsa/201607-15
https://www.securitytracker.com/id/1036037
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.asc
https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.