Network Time Protocol Daemon (ntpd) 3.x / 4.x < 4.2.8p2 Multiple Vulnerabilities

Medium Nessus Plugin ID 83744


The remote NTP server is affected by multiple vulnerabilities.


The version of the remote NTP server is 3.x or 4.x prior to 4.2.8p2.
It is, therefore, affected by the following vulnerabilities :

- The symmetric-key feature in the receive() function requires a correct message authentication code (MAC) only if the MAC field has a nonzero length. A man-in-the-middle attacker can exploit this to spoof packets by omitting the MAC. (CVE-2015-1798)

- A flaw exists in the symmetric-key feature in the receive() function when handling a specially crafted packet sent to one of two hosts that are peering with each other. An attacker can exploit this to cause the next attempt by the servers to synchronize to fail.

- A flaw exists in util/ntp-keygen.c due to the way that the ntp-keygen utility generates MD5 symmetric keys on big-endian systems. A remote attacker can exploit this to more easily guess MD5 symmetric keys and thereby spoof an NTP server or client. (CVE-2015-3405)


Upgrade to NTP version 4.2.8p2 or later.

See Also

Plugin Details

Severity: Medium

ID: 83744

File Name: ntp_4_2_8p2.nasl

Version: 1.11

Type: remote

Family: Misc.

Published: 2015/05/21

Updated: 2019/11/22

Dependencies: 10884

Configuration: Enable paranoid mode

Risk Information

Risk Factor: Medium

CVSS Score Source: CVE-2015-3405

CVSS v2.0

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N

Temporal Vector: CVSS2#E:POC/RL:OF/RC:C

CVSS v3.0

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:ntp:ntp

Required KB Items: NTP/Running, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2015/04/07

Vulnerability Publication Date: 2015/03/30

Reference Information

CVE: CVE-2015-1798, CVE-2015-1799, CVE-2015-2781, CVE-2015-3405

BID: 73950, 73951, 74045

CERT: 374268