Office applications must be configured to specify encryption type in password-protected Office 97-2003 files.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-99655	O365-CO-000008	SV-108759r1_rule		Medium

Description
This policy setting enables you to specify an encryption type for password-protected Office 97-2003 files. If you enable this policy setting, you can specify the type of encryption that Office applications will use to encrypt password-protected files in the older Office 97-2003 file formats. The chosen encryption type must have a corresponding cryptographic service provider (CSP) installed on the computer that encrypts the file. See the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Defaults\Provider\ registry key for a list of CSPs installed on the local computer. Specify the encryption type to use by entering it in the provided text box in the following form: <Encryption Provider>,<Encryption Algorithm>,<Encryption Key Length>. For example, Microsoft Enhanced Cryptographic Provider v1.0,RC4,128 If you do not configure this policy setting, Excel, PowerPoint, and Word use Office 97/2000 Compatible encryption, a proprietary encryption method, to encrypt password-protected Office 97-2003 files.

Description

This policy setting enables you to specify an encryption type for password-protected Office 97-2003 files. If you enable this policy setting, you can specify the type of encryption that Office applications will use to encrypt password-protected files in the older Office 97-2003 file formats. The chosen encryption type must have a corresponding cryptographic service provider (CSP) installed on the computer that encrypts the file. See the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Defaults\Provider\ registry key for a list of CSPs installed on the local computer. Specify the encryption type to use by entering it in the provided text box in the following form: <Encryption Provider>,<Encryption Algorithm>,<Encryption Key Length>. For example, Microsoft Enhanced Cryptographic Provider v1.0,RC4,128 If you do not configure this policy setting, Excel, PowerPoint, and Word use Office 97/2000 Compatible encryption, a proprietary encryption method, to encrypt password-protected Office 97-2003 files.

STIG	Date
Microsoft Office 365 ProPlus Security Technical Implementation Guide	2020-06-17

Details

Check Text ( C-98505r1_chk )
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Office 2016 >> Security Settings >> Encryption type for password protected Office 97-2003 files is set to Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256. Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\microsoft\office\16.0\common\security If the value defaultencryption12 is set to REG_SZ = "Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256", this is not a finding.

Check Text ( C-98505r1_chk )

Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Office 2016 >> Security Settings >> Encryption type for password protected Office 97-2003 files is set to Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256.

Use the Windows Registry Editor to navigate to the following key:

HKCU\software\policies\microsoft\office\16.0\common\security

If the value defaultencryption12 is set to REG_SZ = "Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256", this is not a finding.

Fix Text (F-105339r1_fix)
Set the policy value for User Configuration >> Administrative Templates >> Microsoft Office 2016 >> Security Settings >> Encryption type for password protected Office 97-2003 files to Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256.