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AUSCERT External Security Bulletin Redistribution
2015-10 Out of Cycle Security Bulletin: NTP.org announcement
of multiple vulnerabilities.
26 October 2015
AusCERT Security Bulletin Summary
Publisher: Juniper Networks
Operating System: Juniper
Impact/Access: Access Privileged Data -- Remote/Unauthenticated
Denial of Service -- Remote/Unauthenticated
Provide Misleading Information -- Remote/Unauthenticated
CVE Names: CVE-2015-7871 CVE-2015-7855 CVE-2015-7854
CVE-2015-7853 CVE-2015-7852 CVE-2015-7851
CVE-2015-7850 CVE-2015-7849 CVE-2015-7848
CVE-2015-7705 CVE-2015-7704 CVE-2015-7703
CVE-2015-7702 CVE-2015-7701 CVE-2015-7692
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2015-10 Out of Cycle Security Bulletin: NTP.org announcement of multiple
Security Advisories ID: JSA10711
Last Updated: 23 Oct 2015
This issue can affect any product or platform running NTP.org's NTP daemon.
NTP.org published a security advisory for thirteen vulnerabilities in NTP
software on Oct 21st, 2015. These vulnerabilities may allow remote
unauthenticated attackers to cause Denial(s) of Service(s), disruption of
service(s) by modification of time stamps being issued by the NTP server from
malicious NTP crafted packets, including maliciously crafted NTP
authentication packets and disclosure of information. This can impact DNS
services, as well as certificate chains, such as those used in SSL/https
communications and allow attackers to maliciously inject invalid certificates
as valid which clients would accept as valid.
NTP is not enabled in Junos by default. When NTP is enabled within the [edit
system ntp] hierarchy level of the Junos configuration Junos OS may be
impacted by these vulnerabilities.
If unwanted NTP requests come into a Junos device, the NTP process may process
these requests as valid NTP incoming packets.
On the SRX Series platform, NTP requests coming in from security zones to the
firewall self-traffic are dropped by default unless the 'host-inbound-traffic'
for 'protocol ntp' is explicitly enabled.
These issues have been assigned CVE-2015-7871 CVE-2015-7855 CVE-2015-7854
CVE-2015-7853 CVE-2015-7852 CVE-2015-7851 CVE-2015-7850 CVE-2015-7849
CVE-2015-7848 CVE-2015-7701 CVE-2015-7703 CVE-2015-7704 CVE-2015-7705
CVE-2015-7691 CVE-2015-7692 CVE-2015-7702.
These issues are being tracked as PR 1132181 for Junos OS.
KB16765 - "In which releases are vulnerabilities fixed?" describes which
release vulnerabilities are fixed as per our End of Engineering and End of
Life support policies.
Additional platforms and products are still being reviewed.
This section will be updated as additional fixes for the vulnerabilities are
Juniper has published JSA10613 and JSA10663 previously to mitigate attacks and
exploits against NTP. To mitigate risk of NTP exploits, customers should read
and follow the workaround sections of these JSA's.
To mitigate these exploits:
Authenticate with only trusted higher-stratum servers e.g. if your stratum
is 10, authenticate to only trusted stratum 0 - 9 servers.
Limit the attack surface by implementing firewall filters to only accept
NTP authentication messages from trusted servers.
Some evidence exists that retrieval of time services from Non-NTP.org
NTP-based servers may mitigate these currently-disclosed risks, but is not
If your NTP server is a high level stratum; e.g. stratum 0 or 1; open NTP
server, no known workarounds exists.
Customers are urged to apply the updates as they become available and follow
the Solution section.
How to obtain fixed software:
Security vulnerabilities in Junos are fixed in the next available Maintenance
Release of each supported Junos version. In some cases, a Maintenance Release
is not planned to be available in an appropriate time-frame. For these cases,
Service Releases are made available in order to be more timely. Security
Advisory and Security Notices will indicate which Maintenance and Service
Releases contain fixes for the issues described. Upon request to JTAC,
customers will be provided download instructions for a Service Release.
Although Juniper does not provide formal Release Note documentation for a
Service Release, a list of "PRs fixed" can be provided on request.
2015-10-23: Initial publication
KB16765: In which releases are vulnerabilities fixed?
KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security
Report a Vulnerability - How to Contact the Juniper Networks Security
Incident Response Team
NTP.ORG October 2015 NTP Security Vulnerability Announcement (Medium)
CVE-2015-7871 NAK to the Future: Symmetric association authentication
bypass via crypto-NAK (Cisco ASIG)
CVE-2015-7855 decodenetnum() will ASSERT botch instead of returning FAIL
on some bogus values (IDA)
CVE-2015-7854 Password Length Memory Corruption Vulnerability. (Cisco
CVE-2015-7853 Invalid length data provided by a custom refclock driver
could cause a buffer overflow. (Cisco TALOS)
CVE-2015-7852 ntpq atoascii() Memory Corruption Vulnerability. (Cisco
CVE-2015-7851 saveconfig Directory Traversal Vulnerability. (OpenVMS)
CVSS Score: 7.2 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L)
Risk Level: High
Risk Assessment: Information for how Juniper Networks uses CVSS can be found
at KB16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security
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