The best way to ensure operating system security is to check log files. In UNIX systems, configure the syslog.conf file to tell the syslog daemon to capture relevant logins and messages concerning your Web server.
You can also use the lastlog and last commands to determine who has logged in locally and remotely. The Windows User Manager for Domains program allows you to set auditing levels for the system. The Windows Event Viewer contains a list of logged users, as well as items of interest. Even if you secure your files, remove irrelevant services, install intrusion detection software, and enforce strong passwords, neglecting system logs will seriously impair the security of your e-commerce site.
Operating systems are the core of the computing environment providing users a common and interface to the hardware and software installed on a computer. Exploits in operating system code wreak havoc on computers, giving hackers the ability to steal data and to damage both hardware and software. Operating system security is crucial because it protects the central control system of a computer.

Operating systems are composed of hundreds of thousands of lines of code. Because humans program and debug each operating system, hundreds of vulnerabilities are introduced into the code at development time. These weaknesses, ranging from simple unwanted behavior or error messages to full-scale system crashes and data corruption, can have catastrophic consequences on data management and productivity. Operating system manufacturers, such as Microsoft and Apple, frequently publish updates to the code, called patches, to fix these vulnerabilities and to ensure system stability.