Windows Vista Security: Praxisorientierte Sicherheit für Profis

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Chapter 7: Navigating the Web with Internet Explorer 7

Restricting Permissions Using Security Zones

Security levels and zones are important parts of Internet Explorer’s security features.

You can display security options for Internet Explorer by clicking Tools

➝ Internet

Options, and then clicking the Security tab in the Internet Options dialog box, as

shown in Figure 7-20. The standard levels of security that you can use are:

High

Appropriate for sites that might contain harmful content. With this security

level, Internet Explorer runs with maximum safeguards and with less-secure fea-

tures disabled.

Medium-high

Appropriate for most public Internet sites. With this security level, Internet

Explorer prompts you prior to downloading all potentially unsafe types of con-

tent and disables downloading of unsigned ActiveX controls.

Medium

Appropriate only for trusted sites. With this security level, Internet Explorer

prompts you prior to downloading most potentially unsafe contents and dis-

ables downloading of unsigned ActiveX controls.

Medium-low

Appropriate only for sites on your internal network. With this security level,

Internet Explorer disables downloading of unsigned ActiveX controls but down-

loads and runs most types of content without prompting.

Low

Appropriate only for sites you know are trustworthy, such as secure internal

sites. With this security level, Internet Explorer uses minimal safeguards, and

downloads and runs most types of content without prompts.

Internet Explorer 7 uses security zones to help you restrict permissions according to

where web sites are located and what you know about them. Each security zone is

assigned a default security level. From most trusted to least trusted, the security

zones are:

Local intranet

This zone is used to configure security settings for sites on your local network.

The default security level is Medium-low.

Unlike earlier releases of Windows, Windows Vista can automatically

detect when web sites are on your local network. Windows Vista does

this by checking the network address of the web site and comparing it

to the network address of your computer. Windows Vista also consid-

ers sites bypassed by the proxy server and network paths, such as Uni-

versal Naming Convention (UNC) paths, as being on the local

network.

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Trusted sites

This zone is used to configure security settings for sites that you explicitly trust

and that are considered to be free of content that could damage or harm your

computer. The default security level is Medium.

Internet

This zone is used to configure security settings for sites on the public Internet,

and is used for all sites not placed in other zones. The default security level is

Medium-high.

Restricted sites

This zone is used to configure security settings for sites that could potentially

damage your computer. The default security level is High.

When you are working with the “Local intranet,” “Trusted sites,” and “Restricted

sites” zones, you can specify the web addresses of sites that should be associated

with these zones. With the “Local intranet” zone, you can also control the way Win-

dows Vista detects sites on the local network.

Figure 7-20. Managing the overall security on a per-zone basis