Exchange ActiveSync (EAS) must only use certificate-based authentication to access email.
From MS Exchange 2013 Client Access Server Security Technical Implementation Guide
Part of SRG-APP-000033
Associated with:
CCI-000213
SV-84349r1_rule
Exchange ActiveSync (EAS) must only use certificate-based authentication to access email.
Vulnerability discussion
Identification and Authentication provide the foundation for access control. For EAS to be used effectively on DoD networks, client certificate authentication must be used for communications between the MEM and email server. Additionally, the internal and external URLs must be set to the same address, since all EAS traffic must be tunneled to the device from the MEM.The risk associated with email synchronization with CMD should be mitigated by the introduction of MEM products and is specified in the DoD CIO memo dated 06 Apr 2011. The memo states specifically, "Email redirection from the email server (e.g., Exchange Server) to the device shall be controlled via centrally managed server." When EAS is used on DoD networks, the devices must be managed by an MEM.
Check content
Open the Exchange Management Shell and enter the following commands:
Get-ActiveSyncVirtualDirectory | Select Name, Identity
Get-ActiveSyncVirtualDirectory -Identity 'Microsoft-Server-ActiveSync (Default Web Site)' | fl BasicAuthEnabled, WindowsAuthEnabled, ClientCertAuth, WebSiteSSLEnabled, InternalAuthenticationMethods, ExternalAuthenticationMethods
Note: The Microsoft-Server-ActiveSync (Default Web Site) value must be in quotes.
The command should return the following:
BasicAuthEnabled : False
WindowsAuthEnabled : False
ClientCertAuth : Required
WebSiteSSLEnabled : True
InternalAuthenticationMethods : {Certificate}
ExternalAuthenticationMethods : {Certificate}
If the values above are not returned, this is a finding.
Fix text
Open the Exchange Management Shell and enter the following command:
Set-ActiveSyncVirtualDirectory -Identity ‘\Microsoft-Server-ActiveSync (Default Web Site)’ -BasicAuthEnabled $False -WindowsAuthEnabled $False -ClientCertAuth ‘Required’ -WebSites-InternalAuthenticationMethods ‘Certificate’ -ExternalAuthenticationMethods ‘Certificate’
Note: The Microsoft-Server-ActiveSync (Default Web Site) value must be in quotes.
Pro Tips
Lavender hyperlinks in small type off to the right (of CSS
class id, if you view the page source) point to
globally unique URIs for each document and item. Copy the
link location and paste anywhere you need to talk
unambiguously about these things.
You can obtain data about documents and items in other
formats. Simply provide an HTTP header Accept:
text/turtle or
Accept: application/rdf+xml.
Powered by sagemincer