There are number of security features in Windows Vista. Most of which are newly introduced in this version. Along with them old security features also available with some advanced protection mechanism.
UAC (User Account Control) is the most significant security update in Vista. With this feature, all users, including users with administrative privileges, run in a standard user mode by default. When any action require Administration privilege such as software installation or changing system setting, Windows prompts for Administrator authentication. This security implemented in Vista to protect your computer from malware software. If any of those malware softwares attempts to change any setting or install any software in your system, they will be prompted for consent first. System administrators also have the option to configure the system to require an administrator password for such elevations.
Microsoft added another layer of security 'Windows Defender'. Windows defender goes to scan the system periodically to detect spyware, addition to that it includes Real Time Security Agents which is going to monitor the important settings of the systems if there any system configuration changes caused by spyware.
Windows vista introduced several parental controls. As an administrator it is possible to locking web content and limit web browsing to only Kids website. As well as controlling based on categories such as "Pornography" or "Chatting" and so on. Administrator can restrict other users from executing certain programs. Also there is an option to restrict certain hours of the day when gaming or other activities are permitted.
It also introduced BitLocker Drive Encryption to protect data from a lost or stolen computer. There is a big threat of data theft or exposure from lost or stolen computer. Data on lost or stolen machines can often be viewed by installing a different operating system. BitLocker Drive Encryption is a hardware-enabled data protection feature that helps protect data on a PC when the machine is in unauthorized hands. By encrypting the entire Windows volume, it prevails unauthorized users from accessing Windows file and trying the offline viewing of information on the secured drive.
The Encryption File System (EFS) is a powerful tool for encrypting information on client computers and remote file server to protect them from unauthorized users. EFS support storing user keys as well as administrative recovery keys on smart cards. If smart cards are used for logon, EFS operates in a single Sign On mode, where it uses the logon smart card for file encryption without further prompting for the PIN. The Client Side Cache, which stores offline copies of files from remote servers, can also be encrypted with EFS.
Another way that malicious software makes its way onto a user's machine is by taking advantage of buffer overruns. Address Space Layout Randomization (ASLR) is a defense capability in Windows Vista that makes it harder for malicious code to exploit a system function. Whenever a Windows Vista computer is rebooted, ASLR randomly assigns executable images such as DLLs and EXEs to one of 256 possible locations in memory. This makes it harder for exploit code to locate and there before take advantage of functionality inside the executables.
It is very common in office environment that somehow malware got into one of the systems and from there malware spread into other systems in the local network. To avoid those circumstances vista introduced Network Access Protection (NAP) that fulfills computer health policy validation. Independent hardware and software vendors can plug their security solutions into NAP, so IT administrators can choose the security solutions that meet their unique needs – and NAP helps ensure that every machine on the network makes full use of those solutions.
Vista also includes the much improved Internet Explorer 7, which includes more than a dozen new security enhancements.