HighThe following information summarizes how macro virus protection works under each setting on the Security Level tab in the Security dialog box (Tools menu, Macro submenu) under different conditions. Under all settings, if antivirus software that works with Microsoft Office XP is installed and the file contains macros, the file is scanned for known viruses before it is opened.
High
Macros are automatically disabled, and the file is opened.
Signed macros
The source of the macro and the status of the signature determine how signed macros are handled.
A trusted source. Signature is valid.
Macros are automatically enabled, and the file is opened.
An unknown author. Signature is valid.
A dialog box is displayed with information about the certificate. Macros can be enabled only if the user chooses to trust the author and certification authority. A network administrator can lock the list of trusted sources and prevent the user from adding the developer to the list and enabling the macros.
Any author. Signature is invalid, possibly because of a virus.
User is warned of a possible virus. Macros are automatically disabled.
Any author. Signature validation is not possible because public key is missing or incompatible encryption methods were used.
Any author. The signature was made after the certificate had expired or had been revoked.
User is warned that the signature has expired or been revoked. Macros are automatically disabled.
Medium
Unsigned macros
User is prompted to enable or disable macros.Signed macros
The source of the macro and the status of the signature determine how signed macros are handled.
A trusted source. Signature is valid.
Macros are automatically enabled, and the file is opened.
An unknown author. Signature is valid.
A dialog box is displayed with information about the certificate. The user is prompted to enable or disable macros. The user can choose to trust the developer and certification authority.
Any author. Signature is invalid, possibly because of a virus.
User is warned of a possible virus. Macros are automatically disabled.
Any author. Signature validation is not possible because public key is missing or incompatible encryption methods were used.
User is warned that signature validation is not possible. User is prompted to enable or disable macros.
Any author. The signature was made after the certificate had expired or had been revoked.
User is warned that the signature has expired or been revoked. User is prompted to enable or disable macros.
Low
When security it set to low, all macros are treated equally regardless of origin or certificate status. With low security, you receive no prompt or signature validation and macros are automatically enabled. Use this setting only if you are certain that all macros in your files are from trusted sources.