title: Junos OS: A kernel hang may occur due to a specific loopback filter action command
description: A vulnerability in a specific loopback filter action command, processed in a specific logical order of operation, in a running configuration of Juniper Networks Junos OS, allows an attacker with CLI access and the ability to initiate remote sessions to the loopback interface with the defined action, to hang the kernel. Affected releases are Juniper Networks Junos OS 12.1X46 prior to 12.1X46-D55; 12.3X48 prior to 12.3X48-D35; 14.1 prior to 14.1R8-S4, 14.1R9; 14.1X53 prior to 14.1X53-D40; 14.2 prior to 14.2R4-S9, 14.2R7-S8, 14.2R8; 15.1 prior to 15.1F5-S3, 15.1F6, 15.1R4; 15.1X49 prior to 15.1X49-D60; 15.1X53 prior to 15.1X53-D47; 16.1 prior to 16.1R2. No other Juniper Networks products or platforms are affected by this issue.
problem types: kernel hang
affected:
{
product: Junos OS
vendor: Juniper Networks
versions:
status: affected, version: 12.1X46 prior to 12.1X46-D55
status: affected, version: 12.3X48 prior to 12.3X48-D35
status: affected, version: 14.1 prior to 14.1R8-S4, 14.1R9
status: affected, version: 14.1X53 prior to 14.1X53-D40
status: affected, version: 14.2 prior to 14.2R4-S9, 14.2R7-S8, 14.2R8
status: affected, version: 15.1 prior to 15.1F5-S3, 15.1F6, 15.1R4
status: affected, version: 15.1X49 prior to 15.1X49-D60
status: affected, version: 15.1X53 prior to 15.1X53-D47
status: affected, version: 16.1 prior to 16.1R2
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: LOCAL
availabilityImpact: HIGH
baseScore: 5.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
version: 3.0
]
workarounds: Discontinue the use of allowing remote sessions to be issued from the local device to reach loopback address(es).
It is good security practice to limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the device from trusted, administrative networks or hosts.