Security Threat Assessment of an Internet Security System Using Attack Tree and Vague Sets

Table 1

The possible range of leaf node failures.

Failure possibility
(IP Table configuration errors)	0.30	0.33	0.35	0.37	0.40	0.8	0.9
(address translation failure)	0.10	0.12	0.15	0.18	0.20	0.9	1.0
(authentication failure)	0.80	0.90	0.10	0.11	0.12	0.9	0.9
(Firewall Daemon configuration errors)	0.04	0.04	0.05	0.06	0.06	0.8	0.9
(scan failure)	0.11	0.12	0.13	0.14	0.15	0.9	1.0
(cleanse failure)	0.10	0.10	0.11	0.12	0.12	0.9	1.0
(audit failure)	0.03	0.04	0.05	0.06	0.07	0.9	1.0
(validation failure)	0.03	0.03	0.04	0.05	0.05	0.9	1.0
(DNS configuration errors)	0.08	0.09	0.10	0.11	0.12	0.8	0.9
(monitor service failure)	0.04	0.04	0.05	0.06	0.06	0.9	1.0
(malicious access detected)	0.35	0.37	0.40	0.43	0.45	0.8	1.0
(Transport Layer Security configuration errors)	0.12	0.13	0.14	0.15	0.16	0.8	0.9
(peer entity authentication)	0.15	0.16	0.20	0.24	0.25	0.8	1.0
(security parameter negotiation)	0.27	0.28	0.30	0.32	0.33	0.8	0.9
(POP3 configuration errors)	0.16	0.17	0.18	0.19	0.20	0.8	0.9
(entity authentication)	0.22	0.24	0.25	0.26	0.28	0.8	1.0
(entry security parameter)	0.38	0.39	0.40	0.41	0.42	0.8	0.9
(security parameter authentication)	0.07	0.08	0.09	0.10	0.11	0.8	1.0
(key generation)	0.05	0.06	0.07	0.08	0.09	0.8	0.9
(data confidentiality)	0.03	0.03	0.04	0.05	0.05	0.9	0.9