Title

Encryption type for password protected Open XML files - Office (Cat II impact)

Discussion

If unencrypted files are intercepted, sensitive information in the files can be compromised. To protect information confidentiality, 2007 Office application files can be encrypted and password protected. Only users who know the correct password will be able to decrypt such files. On computers that run Windows Vista, the default cryptographic service provider (CSP) is Microsoft Enhanced RSA and AES Cryptographic Provider, AES-128, 128-bit. On computers that run Windows XP, the default CSP is Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype), AES-128, 128-bit.

Check Content

If Office 2007 NON XP OS: The policy value for User Configuration -> Administrative Templates -> Microsoft Office 2007 system -> Security Settings “Encryption type for password protected Office Open XML files” will minimally be set to “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider,AES 128,128)”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\12.0\Common\Security Criteria: If the minimum value OpenXMLEncryption is REG_SZ = “Microsoft Enhanced RSA and AES Cryptographic Provider,AES 128,128”, this is not a finding. If Office 2007 with XP OS: The policy value for User Configuration -> Administrative Templates -> Microsoft Office 2007 system -> Security Settings “Encryption type for password protected Office Open XML files” will minimally be set to “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype),AES 128,128)”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\12.0\Common\Security Criteria: If the minimum value OpenXMLEncryption is REG_SZ = “Microsoft Enhanced RSA and AES Cryptographic Provider(Prototype),AES 128,128”, this is not a finding. NOTE: “Microsoft Enhanced RSA and AES Cryptographic Provider,AES 128,128" or “Microsoft Enhanced RSA and AES Cryptographic Provider(Prototype),AES 128,128" is minimum setting required where can be up to key length of 256 if environment will support as “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256)" or “Enabled Microsoft Enhanced RSA and AES Cryptographic Provider(Prototype),AES 256,256".

Fix Text

The policy value for User Configuration -> Administrative Templates -> Microsoft Office 2007 system -> Security Settings “Encryption type for password protected Office Open XML files” will be set to “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider,AES 128,128)” for NON XP OS's or “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype),AES 128,128)” for XP OS. NOTE: “Microsoft Enhanced RSA and AES Cryptographic Provider,AES 128,128" is minimum setting required where can be up to key length of 256 if environment will support as “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider,AES 256,256)” or “Enabled (Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype),AES 256,256)”

Additional Identifiers

Rule ID: SV-18758r1_rule

Vulnerability ID: V-17619

Group Title:

Expert Comments

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