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.