Vấn đề này có thể được đấu tranh bằng cách nâng cấp các thành phần nhưng là một lỗ hổng vốn có trong bất kỳ đơn vị. Kinh nghiệm của tôi với hệ điều hành đã cho thấy họ phát triển dễ bị tổn thương được biết đến của nó hóa đầu tiên công khai trong vòng một tháng được phát hành ra công chúng. Các hệ thống điều hành đã giám sát gần nhất (Windows NT, Solaris, HP-UX, Irix, và Linux) đã tạo ra giữa 15 và 50 lỗ hổng bảo mật mỗi năm cho mỗi người trong số. | Computer Vulnerabilities Fault Page 31 Work Directories with World Access As a precursor to a race condition a program uses a work directory with world access. This allows for the possibility of race conditions altering of information or even a user hiding files in a location outside of their home directory. Sample Vulnerability Common Configuration Problem usr spool crontab configuration By default on many old version of UNIX the usr spool crontab was distributed world readable and world writable. Any user could modify the usr spool crontab root file to execute commands as root. In this case too much access was given and taken advantage of. Even in a shared computer environment strict controls need to be placed on whom can use files at any particular time. One of the great advantages of UNIX is that many people with many types of access can use it simultaneously and protection needs to be provided so that one user cannot adversely affect the other users. Installed In Wrong Place Although modern software is often dynamic and can be placed anywhere on a system it can be installed in the wrong location that may allow either unusual behavior from the program or having others have access to the program that they should not. Over-Optimistic Security Permissions One program that has had a number of problems with security is the install program which by default on many platforms was setuid root. Although it was argued for a long time that the security inside of install was good enough to prevent abuse eventually the setuid bit was removed. What follows are two examples of problems install has had in the past. Sample Vulnerability install general Administrator Access cp etc passwd tmp passwd echo intruder 0 0 The Intruder bin sh etc passwd install -d -o username etc cp tmp passwd etc Sample Vulnerability install general Administrator Access cp etc passwd tmp passwd echo intruder 0 0 The Intruder bin sh etc passwd install -d -o username etc cp tmp passwd etc passwd install
