TY JOUR TI VIRTUAL LABORATORY CREATION FOR DISTRIBUTED INFORMATION SYSTEM SAFETY TESTING KW testing for penetration KW virtual laboratory KW Kali Linux KW Metasploitable 2 KW NAT KW Drupal JO Bulletin of Bryansk state technical university AU Krasov, A.V. AU Shterenberg, S.I. AU Moskal'chuk, A.I. PY 2020 IS 2020 PB Bryansk State Technical University