Title

WEBSERVICE functions must be disabled. (Cat II impact)

Discussion

The WEBSERVICE function option, when used in an Excel spreadsheet, returns data from a web service on the Internet or Intranet. If allowed to be used, security is significantly reduced by allowing information disclosure to third party web services and could potentially introduce malicious content to the local network. The WEBSERVICE function must be disabled in Excel and configured to notify user if a WEBSERVICE function is present in an Excel spreadsheet.

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> " WEBSERVICE Function Notification Settings" is set to "Enabled: Disable all with notifications". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\Microsoft\office\15.0\excel\security Criteria: If the value webservicefunctionwarnings is REG_DWORD = 1, this is not a finding.

Fix Text

Set policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> " WEBSERVICE Function Notification Settings" is set to "Enabled: Disable all with notifications".

Additional Identifiers

Rule ID: SV-242373r961086_rule

Vulnerability ID: V-242373

Group Title: SRG-APP-000207

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.