title: Junos OS: A remote unauthenticated attacker can consume large amounts of CPU and/or memory through telnetd
description: A vulnerability in telnetd service on Junos OS allows a remote attacker to cause a limited memory and/or CPU consumption denial of service attack. This issue was found during internal product security testing. Affected releases are Juniper Networks Junos OS 12.1X46 prior to 12.1X46-D45; 12.3X48 prior to 12.3X48-D30; 14.1 prior to 14.1R4-S9, 14.1R8; 14.2 prior to 14.2R6; 15.1 prior to 15.1F5, 15.1R3; 15.1X49 prior to 15.1X49-D40; 15.1X53 prior to 15.1X53-D232, 15.1X53-D47.
problem types: resource consumption
affected:
{
product: Junos OS
vendor: Juniper Networks
versions:
status: affected, version: 12.1X46 prior to 12.1X46-D45
status: affected, version: 12.3X48 prior to 12.3X48-D30
status: affected, version: 14.1 prior to 14.1R4-S9, 14.1R8
status: affected, version: 14.2 prior to 14.2R6
status: affected, version: 15.1 prior to 15.1F5, 15.1R3
status: affected, version: 15.1X49 prior to 15.1X49-D40
status: affected, version: 15.1X53 prior to 15.1X53-D47, 15.1X53-D232
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 5.3
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
version: 3.0
]
workarounds: Disable telnet services.
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.