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What would prevent an ISAPI extension from opening a socket on IIS 6?



What would prevent an ISAPI extension from opening a socket on IIS 6? David_Cordes NO[at]SPAM hotmail.com
11/5/2004 3:31:02 PM
iis security: Problem
=-=-=-=-
I am working with a customer who has installed IIS 6. They have
installed two different products that communicate with other servers
through ISAPI Filters. In both products the ISAPI filters work
correctly until they try to obtain a socket.

Both of these programs are trying to communicate to different server
process on the same machine with 127.0.0.1 as the address. Both
server processes show every indication of working.

I suspect there is an IIS or Windows Server 2003 setting I am missing.

Technical Details
=-=--==-=--=-==-=-
One of the products is Open Source so I was able to determine the
exact line that gets called:

socket(AF_INET, SOCK_STREAM, 0);

The WinSock2 API using WSAGetLastError() indicates that permission is
denied.

The customer can use other programs (such as telnet) to obtain a
socket, open a connection to the local server process. The problem
appears only to occur when running within IIS 6 with the IUSR account.

Already Checked:
=-=-=-=-=-=-=-=-
- TCP/IP Filterting on the adaptor turned off.
- Local security policy has not applied any of the ip policies and all
network access user settings are identical to those on my Windows
Server 2003 machine.
- Customer indicates that no firewalls are running on this machine and
since I am connecting via 127.0.0.1 an external firewall should not
have any bearing here I would expect. I also do not suspect a
firewall, firewalls usually block communications but do not prevent a
socket from even being obtained from the OS.

Re: What would prevent an ISAPI extension from opening a socket on IIS 6? David Wang [Msft]
11/5/2004 10:46:44 PM
Are you talking about an ISAPI Extension or an ISAPI Filter?

ISAPI Filter on IIS6 would be running as process identity, which is either
LocalSystem in IIS5 Compatibility Mode or the AppPool Identity in IIS6
Worker Process Isolation Mode.

ISAPI Extension would be the impersonated identity, which is either the
configured anonymous user if anonymous authentication, or likely to be the
logged in browser user for any other authentication type.

I'm not certain if Windows Server 2003 has decided to deny certain user
identities access to Networking. Are you saying that the Winsock call works
on your Windows Server 2003 but not your customer's?

--
//David
IIS
This posting is provided "AS IS" with no warranties, and confers no rights.
//
[quoted text, click to view]
Problem
=-=-=-=-
I am working with a customer who has installed IIS 6. They have
installed two different products that communicate with other servers
through ISAPI Filters. In both products the ISAPI filters work
correctly until they try to obtain a socket.

Both of these programs are trying to communicate to different server
process on the same machine with 127.0.0.1 as the address. Both
server processes show every indication of working.

I suspect there is an IIS or Windows Server 2003 setting I am missing.

Technical Details
=-=--==-=--=-==-=-
One of the products is Open Source so I was able to determine the
exact line that gets called:

socket(AF_INET, SOCK_STREAM, 0);

The WinSock2 API using WSAGetLastError() indicates that permission is
denied.

The customer can use other programs (such as telnet) to obtain a
socket, open a connection to the local server process. The problem
appears only to occur when running within IIS 6 with the IUSR account.

Already Checked:
=-=-=-=-=-=-=-=-
- TCP/IP Filterting on the adaptor turned off.
- Local security policy has not applied any of the ip policies and all
network access user settings are identical to those on my Windows
Server 2003 machine.
- Customer indicates that no firewalls are running on this machine and
since I am connecting via 127.0.0.1 an external firewall should not
have any bearing here I would expect. I also do not suspect a
firewall, firewalls usually block communications but do not prevent a
socket from even being obtained from the OS.

Any suggestions are appreciated. Thank you.

Re: What would prevent an ISAPI extension from opening a socket on IIS 6? David_Cordes NO[at]SPAM hotmail.com
11/8/2004 10:28:42 AM
They are two ISAPI Filters each made by different company that makes a
network connection. Both fail when they try to make that network
connection only on one customer's machine. They both work on my
machine and many other customers' machines.

I am collecting the customer's application pool settings to see
whether they are in isolation mode and if not which identity they are
using.

However, I am not sure how a user account can be configured in such a
way as to make opening any network connection impossible. Other
accounts can make network connections. Did you have a particular
setting in mind? I looked through the local security policy settings
for "Security Options" and confirmed that "Network access" settings
made sense when compared to my machine.

--- David



[quoted text, click to view]
Re: What would prevent an ISAPI extension from opening a socket on IIS 6? David Wang [Msft]
11/8/2004 9:09:41 PM
Yeah, I can't think of anything else to check. I'm curious about the user
identity that is executing the ISAPI Filter code and looking through
secpol.msc to see if any privileges are missing relative to your working
ones.

--
//David
IIS
This posting is provided "AS IS" with no warranties, and confers no rights.
//
[quoted text, click to view]
They are two ISAPI Filters each made by different company that makes a
network connection. Both fail when they try to make that network
connection only on one customer's machine. They both work on my
machine and many other customers' machines.

I am collecting the customer's application pool settings to see
whether they are in isolation mode and if not which identity they are
using.

However, I am not sure how a user account can be configured in such a
way as to make opening any network connection impossible. Other
accounts can make network connections. Did you have a particular
setting in mind? I looked through the local security policy settings
for "Security Options" and confirmed that "Network access" settings
made sense when compared to my machine.

--- David



[quoted text, click to view]

Re: What would prevent an ISAPI extension from opening a socket on IIS 6? David_Cordes NO[at]SPAM hotmail.com
11/9/2004 3:43:08 PM
Sadly we may never find out :-) The customer tried a re-installation
of IIS which didn't work, but then re-installed the OS and the problem
vanished.

--- David

[quoted text, click to view]
Re: What would prevent an ISAPI extension from opening a socket on IIS 6? David Wang [Msft]
11/9/2004 8:19:36 PM
Well, I'm happy that the problem was "solved", though I tend to like knowing
why it worked vs the fact it did. Though I totally understand from a
business perspective, one values the fact that something works and not
necessarily why/how.

--
//David
IIS
This posting is provided "AS IS" with no warranties, and confers no rights.
//
[quoted text, click to view]
Sadly we may never find out :-) The customer tried a re-installation
of IIS which didn't work, but then re-installed the OS and the problem
vanished.

--- David

[quoted text, click to view]

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