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computer network internet security phần 7

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và quản lý thích hợp. Điều quan trọng nhất, an ninh thông tin tốt đòi hỏi phải nhận thức ở tất cả các cấp của tổ chức và hỗ trợ vững chắc có thể nhìn thấy từ các quản lý cao nhất. Chỉ khi khácHệ thống Access Control List (ACL) điều khiển việc tạo ra các thông điệp kiểm toán. | OLE2 technology to efficiently extract only that portion of files that can carry viruses Pattern matching for detection of known viruses as well as intelligent rule-based scanning to detect unknown viruses 7.2.0 Background Despite a significant increase in the usage of anti-virus products the rate of computer virus infection in corporate America has nearly tripled in the past year according to a survey released in April 1997 by the International Computer Security Association ICSA formerly the National Computer Security Association. Virtually all medium and large organizations in North America experienced at least one computer virus infection firsthand and the survey indicated that about 40 percent of all computers used in the surveyed companies would experience a virus infection within a year. Macro viruses which unlike their predecessors are carried in common word processing documents and spreadsheets are the biggest problem representing 80 of all infections. Moreover the instances of macro virus infection doubled about every four months in 1996. This makes these viruses the fastest to spread in the history of the ICSA. The Number One macro virus encountered in the survey by far was the Concept virus also known as prank macro wm-Concept winword.Concept wordmacro.Concept ww6 and ww6macro. Within months of its discovery in the fall of 1995 the Concept virus accounted for more than three times the number of virus encounters reported for the previous leader the Form virus. Today the Concept virus has infected almost one-half of all ICSA survey sites see Figure 1 . Figure 1. The Concept virus and other Word macro viruses were the dominant viruses encountered in 1997 according to a virus prevalence survey conducted by the International Computer Security Association. Perhaps even more worrying than the meteoric rise in infections by this particular virus is what it bodes for the future. Microsoft Word trade Microsoft Excel trade and other document and spreadsheet files