CVE-2016-4921

Junos: IPv6 denial of service vulnerability due to resource exhaustion (CVE-2016-4921)

Description

By flooding a Juniper Networks router running Junos OS with specially crafted IPv6 traffic, all available resources can be consumed, leading to the inability to store next hop information for legitimate traffic. In extreme cases, the crafted IPv6 traffic may result in a total resource exhaustion and kernel panic. The issue is triggered by traffic destined to the router. Transit traffic does not trigger the vulnerability. This issue only affects devices with IPv6 enabled and configured. Devices not configured to process IPv6 traffic are unaffected by this vulnerability. This issue was found during internal product security testing. Juniper SIRT is not aware of any malicious exploitation of this vulnerability. Affected releases are Juniper Networks Junos OS 11.4 prior to 11.4R13-S3; 12.3 prior to 12.3R3-S4; 12.3X48 prior to 12.3X48-D30; 13.3 prior to 13.3R10, 13.3R4-S11; 14.1 prior to 14.1R2-S8, 14.1R4-S12, 14.1R8; 14.1X53 prior to 14.1X53-D28, 14.1X53-D40; 14.1X55 prior to 14.1X55-D35; 14.2 prior to 14.2R3-S10, 14.2R4-S7, 14.2R6; 15.1 prior to 15.1F2-S5, 15.1F5-S2, 15.1F6, 15.1R3; 15.1X49 prior to 15.1X49-D40; 15.1X53 prior to 15.1X53-D57, 15.1X53-D70.

Remediation

Workaround:

  • Limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the router via IPv6 only from trusted, administrative networks or hosts.

Category

7.5
CVSS
Severity: High
CVSS 3.0 •
CVSS 2.0 •
EPSS 1.35% Top 25%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA10762 vendor advisory
http://www.securitytracker.com/id/1037014 third party advisory vdb entry
http://www.securityfocus.com/bid/93532 third party advisory vdb entry

Frequently Asked Questions

What is the severity of CVE-2016-4921?
CVE-2016-4921 has been scored as a high severity vulnerability.
How to fix CVE-2016-4921?
As a workaround for remediating CVE-2016-4921: Limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the router via IPv6 only from trusted, administrative networks or hosts.
Is CVE-2016-4921 being actively exploited in the wild?
It is possible that CVE-2016-4921 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2016-4921?
CVE-2016-4921 affects Juniper Networks Junos OS.
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