title: Junos OS: Short MacSec keys may allow man-in-the-middle attacks.
description: If all 64 digits of the connectivity association name (CKN) key or all 32 digits of the connectivity association key (CAK) key are not configured, all remaining digits will be auto-configured to 0. Hence, Juniper devices configured with short MacSec keys are at risk to an increased likelihood that an attacker will discover the secret passphrases configured for these keys through dictionary-based and brute-force-based attacks using spoofed packets. Affected releases are Juniper Networks Junos OS: 14.1 versions prior to 14.1R10, 14.1R9; 14.1X53 versions prior to 14.1X53-D47; 15.1 versions prior to 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D100; 15.1X53 versions prior to 15.1X53-D59; 16.1 versions prior to 16.1R3-S8, 16.1R4-S8, 16.1R5; 16.2 versions prior to 16.2R1-S6, 16.2R2; 17.1 versions prior to 17.1R2.
problem types: weak encryption
man-in-the-middle attack
brute force attack
dictionary attack
affected:
{
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 14.1R10, 14.1R9, status: affected, version: 14.1, versionType: custom
lessThan: 14.1X53-D47, status: affected, version: 14.1X53, versionType: custom
lessThan: 15.1R4-S9, 15.1R6-S6, 15.1R7, status: affected, version: 15.1, versionType: custom
lessThan: 15.1X49-D100, status: affected, version: 15.1X49, versionType: custom
lessThan: 15.1X53-D59, status: affected, version: 15.1X53, versionType: custom
lessThan: 16.1R3-S8, 16.1R4-S8, 16.1R5, status: affected, version: 16.1, versionType: custom
lessThan: 16.2R1-S6, 16.2R2, status: affected, version: 16.2, versionType: custom
lessThan: 17.1R2, status: affected, version: 17.1, versionType: custom
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: HIGH
baseScore: 8.8
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: NONE
scope: CHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
version: 3.0
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: The following software releases have been updated to resolve this specific issue: 14.1R9, 14.1X53-D47, 15.1R4-S9, 15.1R6-S6, 15.1R7, 15.1X49-D100, 15.1X53-D59, 16.1R3-S8, 16.1R4-S8, 16.1R5, 16.2R1-S6, 16.2R2, 17.1R2, 17.2R1 and all subsequent releases.
workarounds: Configure all 64 digits of a CKN.
Configure all 32 digits of a CAK.
See the junos task topic macsec for further information.