Scientific Linux Security Update : ntp on SL6.x, SL7.x i386/x86_64

Medium Nessus Plugin ID 91644


The remote Scientific Linux host is missing one or more security updates.


Security Fix(es) :

- It was found that when NTP was configured in broadcast mode, a remote attacker could broadcast packets with bad authentication to all clients. The clients, upon receiving the malformed packets, would break the association with the broadcast server, causing them to become out of sync over a longer period of time.

- A denial of service flaw was found in the way NTP handled preemptable client associations. A remote attacker could send several crypto NAK packets to a victim client, each with a spoofed source address of an existing associated peer, preventing that client from synchronizing its time. (CVE-2016-1547)

- It was found that an ntpd client could be forced to change from basic client/server mode to the interleaved symmetric mode. A remote attacker could use a spoofed packet that, when processed by an ntpd client, would cause that client to reject all future legitimate server responses, effectively disabling time synchronization on that client. (CVE-2016-1548)

- A flaw was found in the way NTP's libntp performed message authentication. An attacker able to observe the timing of the comparison function used in packet authentication could potentially use this flaw to recover the message digest. (CVE-2016-1550)

- An out-of-bounds access flaw was found in the way ntpd processed certain packets. An authenticated attacker could use a crafted packet to create a peer association with hmode of 7 and larger, which could potentially (although highly unlikely) cause ntpd to crash.

The CVE-2016-1548 issue was discovered by Miroslav Lichvar (Red Hat).


Update the affected packages.

See Also

Plugin Details

Severity: Medium

ID: 91644

File Name: sl_20160531_ntp_on_SL6_x.nasl

Version: $Revision: 2.4 $

Type: local

Agent: unix

Published: 2016/06/17

Modified: 2017/02/13

Dependencies: 12634

Risk Information

Risk Factor: Medium


Base Score: 6.4

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


Base Score: 7.5

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

Vulnerability Information

CPE: x-cpe:/o:fermilab:scientific_linux

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/RedHat/release, Host/RedHat/rpm-list

Patch Publication Date: 2016/05/31

Reference Information

CVE: CVE-2015-7979, CVE-2016-1547, CVE-2016-1548, CVE-2016-1550, CVE-2016-2518