Vulnerability identifier: #VU29542

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-8956

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ntp
Server applications / Other server solutions

Vendor: ntp.org

Description

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

The vulnerability exists due to insufficient validation of user-supplied input when processing NTP packets. A remote attacker that controls a slave server or is part of the same broadcast can prevent a broadcast client from synchronizing its clock with a broadcast NTP server via spoofed mode 3 and mode 5 packets.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ntp: 4.2.8p10 - 4.2.8p13

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CPE

• cpe:2.3:a:ntp_org:ntp:4.2.8p10:*:*:*:*:*:*:*
• cpe:2.3:a:ntp_org:ntp:4.2.8p11:*:*:*:*:*:*:*
• cpe:2.3:a:ntp_org:ntp:4.2.8p12:*:*:*:*:*:*:*
• cpe:2.3:a:ntp_org:ntp:4.2.8p13:*:*:*:*:*:*:*

External links
http://www.ntp.org/
http://arxiv.org/abs/2005.01783
http://nikhiltripathi.in/NTP_attack.pdf
http://security.netapp.com/advisory/ntap-20200518-0006/
http://tools.ietf.org/html/rfc5905

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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