Computer-based authentication / authorization fails with Integrated Web Authentication (IWA)


Article ID: 165575


Updated On:


ProxySG Software - SGOS


Certain applications / User-Agents will perform authentication with their computer accounts. This is generally observed with Windows Vista and Windows 7. Computer accounts are similar to user accounts in several ways – they have a password, and they can belong to groups. However, by default, computer accounts belong only to the 'Domain Computers' group.

For example, the Windows Update agent may authenticate with the computer's account and result in forbidden/denied access :

Hypertext Transfer Protocol
    HEAD HTTP/1.1\r\n
    Accept: */*\r\n
    User-Agent: Windows-Update-Agent\r\n
    Proxy-Connection: Keep-Alive\r\n
    [truncated] Proxy-Authorization: NTLM         NTLM Secure Service Provider
            NTLMSSP identifier: NTLMSSP
            NTLM Message Type: NTLMSSP_AUTH (0x00000003)
            Lan Manager Response: 000000000000000000000000000000000000000000000000
            NTLM Client Challenge: 0000000000000000
            NTLM Response: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx...
            NTLM Client Challenge: xxxxxxxxxxxxxxxx
            Domain name: KLDEV
            User name: BLUECOAT1$           <<<<< Computer Account / Host name is sent as the username
            Host name: BLUECOAT1            <<<<< Computer hostname
            Session Key: Empty
            Flags: 0xa2888205
            Version 6.1 (Build 7600); NTLM Current Revision 15

HTTP/1.1 403 Forbidden
Cache-Control: no-cache
Pragma: no-cache
Content-Type: text/html; charset=utf-8
Proxy-Connection: Keep-Alive
Connection: Keep-Alive
Content-Length: 572



If your organization's security policy allows computer authenticated accounts to access the Internet, the following policy should address the problem.

        realm="IWA_Realm_Name" group="DOMAIN\Domain Computers" ALLOW


        realm="IWA_Realm_Name" group="DOMAIN\Domain Computers" user.login.log_out(yes)

The 'Domain Computers' is available as a source Group object in the VPM's Web Access Layer, similar as other group objects. Hence, the CPL above can also be applied fom the VPM.


Do not use any IP-based surrogate such as Proxy-IP for authentication because the ProxySG may not reauthenticate user traffic within the cached duration. If you need to use an IP-based surrogate, use the user.login.log_out(yes) policy above.



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