Summary:  In the wake of a litany of hack invasions, sophisticated virus attacks, and the increasingly Byzantine and ever changing imbroglio of MS Windows permissions tiers and hidden, so-called services, it has become necessary to define a security policy document as a general guideline for installing MS Windows 2000. The services and permissions complexities and the lack of decent documentation in how to deal with them in MS Windows 2000 has brought about the need for this document. This document is not only an meant to be a guideline for in house skyBuilders MS Windows 2000 installations, but also as a template for organizations needing to address these same issues.
Categories to be covered are:
Why you should use the EVERYONE group instead of the IUSR_[host machine]
account:
I. Defining Users:
A problem occurs when you change the IWAM account's password through NT USERMGR without informing IIS of the changes. You need to update IIS manually because the IWAM account does not have the same password synchronization option that the IUSR account does. IUSR's password synchronization option automatically synchronizes any changes in USRMGR with the IUSR's password stored in the metabase. If you change the password to the IWAM account in USERMGR, you will also need to make the same change to the MTS packages for out-of-process applications that you have already created for IIS. You also need to make the change to the WAMUserPass property in the metabase, which is where IIS stores the IWAM account information that it will use when it is creating new out-of-process applications in the future.
Here I shall excerpt from Mark Reynolds, a link to whose document appears at the bottom of this document:
The everyone group encompasses the Users group, the IUSR_[host machine]
account, and the IWAM_[host machine] account.
IIS 5.0 uses two separate accounts to execute web pages. When anonymous
authentication is used IIS uses the IUSR_[host machine] account to view those pages.
However, IWAM_[host machine] is used to start up a separate process called DLLHOST.EXE.
All ASP, COM components, or other ISAPI extensions (ASP is considered an ISAPI
extension) are run inside this DLLHOST.EXE. This is primarily for stability
purposes. If a custom COM component called from an ASP page crashes (Access
Violates thus shutting down the process) it will not effect INETINFO.EXE. This
means the web service will continue to run.
There are two protection levels in IIS 4.0:
Default - IIS 4.0 runs all "Applications" In-Process meaning inside the INETINFO.EXE process, which gets started up by the SYSTEM account. When web pages are viewed the particular thread that is serving the page is run under the context of the IUSR_[host machine] account. HTM, ASP and any other ISAPI extensions are run inside the INETINFO.EXE process.
Run in Separate Memory Space (Isolated Process) - This is also knows as Out-Of-Process. This uses the IWAM_[host machine] account to spawn a separate MTX.EXE process that runs ASP and other ISAPI extensions.
There are three protection levels in IIS 5.0:
Low (IIS Process) - This setting is similar to the default setting under IIS 4.0. All web pages whether HTM or ASP are run inside the INETINFO.EXE process.
Medium (Pooled) - This is the default. As with IIS 4.0 this setting starts a separate process called DLLHOST.EXE where all ASP and COM components are run. This process is started by the IWAM_[host machine] account just as in IIS 4.0. Also, this setting is known as pooled because even if there are 5000 different web sites running in IIS, they will all share this single DLLHOST.EXE for executing ASP pages (Windows 2000 replaces MTX.EXE with DLLHOST.EXE).
High (Isolated) - This setting starts a dedicated DLLHOST.EXE for that particular web site or application. If you had 5 web sites each set on High protection you would see five DLLHOST.EXE processes plus one additional DLLHOST.EXE that COM+ starts under the "System Application" for a total of six DLLHOST.EXE's.
To restore default NTFS permissions for Windows 2000 please see:
Q266118 How to Restore the Default NTFS Permissions for Windows 2000
II. Defining File and Folder Permissions:
As general matter of policy is good practice to locate operating system and service programming files away from their traditional, and, therefore, vulnerable drive locations. We recommend that whenever possible to avoid using the C: drive, which is where many viruses begin their search for service programs to hijack. Please refer to the previous item (I.7) for a discussion of actual user accounts with their associated privileges for each of the following directories here.
III. Defining Allowable Services and Ports:
Many server services open windows of vulnerability into your server machine. Services such as telnet, FTP, SMTP, and even DNS and and web browsing can open your server up to hijacking. Standard port numbers can can remapped to help fool invaders as what ports may be open of your server. You should ask yourself questions such as, should a web server allow the use of a web browser? A great deal of them may be non-essential to the operation of a specific server machine. Services open communication ports which make a server vulnerable. For security purposes it is recommended that all non-essential services be disabled. Many services which create vulnerability can operate through a firewall by means of forwarders or proxy methods, but these topics are far beyond the scope of this document.
Some services are installed by third party software. For instance a "good", but non-essential, third party service is the Norton AntiVirus Client service. Such a service probably should be not disabled.
Other times services can actually be installed by viruses. Take a look at this brief link to see what the notorious Funlove virus does to your registry to act as a service.
What follows is a comprehensive list of MS Windows 2000 Services. It is presently not clear to me what constitutes a minimum of these services for MS Windows 2000 OS to function. Suggestions and recommendations are welcome as to how to tailor various of these services. We will assume that the server you are installing will be primarily a web server, though it may perform other functions such as DNS.
Key: E = Essential, D = Dangerous, O = Reasonable Option to Retain
Alphabetical Listing of All Windows Services | |||
Service / | Dependencies | ||
Description | Depends on: | Supports: | |
1. | Alerter | Workstation | Nothing |
Notifies selected users and computers of administrative alerts. | |||
2. | Application Management | Nothing | Nothing |
Provides software installation services such as Assign, Publish, and Remove. | |||
3. | Boot Information Negotiation Layer | Server | Nothing |
Provides the ability to install Windows 2000 Professional on PXE remote boot-enabled client computers. | |||
4. | ClipBook | Network DDE | Nothing |
Supports ClipBook Viewer, which allows pages to be seen by remote ClipBooks. | |||
5. | COM+ Event System | Remote Procedure Call (RPC) | Nothing |
E | Provides automatic distribution of events to subscribing COM components. | ||
6. | Computer Browser | Server, Workstation | Nothing |
O | Maintains an up-to-date list of computers on your network and supplies the list to programs that request it. | ||
7. | DefWatch | Nothing | Nothing |
O | NA - It is used by Norton AntiVirus, but otherwise no information. | ||
8. | DHCP Client | Nothing | Nothing |
O | Manages network configuration by registering and updating IP addresses and DNS names. | ||
9. | DHCP Server | Remote Procedure Call, Security Accounts Manager | Nothing |
Provides dynamic IP address assignment and network configuration for Dynamic Host Configuration Protocol (DHCP) clients. | |||
10. | Distributed File System | Server, Workstation | Nothing |
Manages logical volumes distributed across a local or wide area network. | |||
11. | Distributed Link Tracking Client | Remote Procedure Call | Nothing |
Sends notifications of files moving between NTFS volumes in a network domain. | |||
12. | Distributed Link Tracking Server | Remote Procedure Call | Nothing |
Stores information so that files moved between volumes can be tracked for each volume in the domain. | |||
13. | Distributed Transaction Coordinator | Remote Procedure Call, Security Accounts Manager | Nothing |
Coordinates transactions that are distributed across two or more databases, message queues, file systems, or other transaction protected resource managers. | |||
14. | DNS Client | Nothing | Nothing |
Resolves and caches Domain Name System (DNS) names. | |||
15. | DNS Server | NT LM Security Support Layer, Remote Procedure Call (RPC) | Nothing |
O | Answers query and update requests for Domain Name System (DNS) names. | ||
16. | Event Log | Nothing | Nothing |
E | Logs event messages issued by programs and Windows. Event Log reports contain information that can be useful in diagnosing problems. Reports are viewed in Event Viewer. | ||
17. | Fax Service | Plug and Play, Print Spooler, RPC, Telephony | Nothing |
Helps you send and receive faxes | |||
18. | File Replication | Event Log, RPC | Nothing |
Maintains file synchronization of file directory contents among multiple servers. | |||
19. | File Server for Macintosh | Workstation | Nothing |
Enables Macintosh users to store and access files on this Windows server machine. | |||
20. | FTP Publishing Service | IIS Admin Service | Nothing |
D | Provides FTP connectivity and administration through the Internet Information Services snap-in. | ||
21. | IIS Admin Service | ProtectedStoragee, RPC | FTP Publishing, SMTP, WWW Publishing Service |
E | Allows administration of Web and FTP services through the Internet Information Services snap-in. | ||
22. | Indexing Service | RPC | Nothing |
O | Makes a web site documents searchable through a browser interface. | ||
23. | Intel Alert Handler | Intel PDS | Nothing |
NA | |||
24. | Intel Alert Originator | Intel PDS | Nothing |
NA | |||
25. | Intel File Transfer | Intel PDS | Nothing |
NA | |||
26. | Intel PDS | Nothing | Intel Alert Handler, Intel Alert Originator, Intel File Transfer |
NA | |||
27. | Internet Authentication Service | RPC | Nothing |
Enables authentication, authorization and accounting of dial-up and VPN users. IAS supports the RADIUS protocol. | |||
28. | Internet Connection Sharing | Remote Access Connection Manager | Nothing |
Provides network address translation, addressing, and name resolution services for all computers on your home network through a dial-up connection. | |||
29. | Intersite Messaging | Security Accounts Manager | Nothing |
Allows sending and receiving messages between Windows Advanced Server sites. | |||
30. | IPSEC Policy Agent | RPC | Nothing |
Manages IP security policy and starts the ISAKMP/Oakley (IKE) and the IP security driver. | |||
31. | Kerberos Key Distribution Center | RPC | Nothing |
O | Generates session keys and grants service tickets for mutual client/server authentication. | ||
32. | License Logging Service | Nothing | Nothing |
NA | |||
33. | Logical Disk Manager | Nothing | Nothing |
Logical Disk Manager Watchdog Service. | |||
34. | Logical Disk Manager Administrative Service | Nothing | Nothing |
Administrative service for disk management requests. | |||
35. | Messenger | RPC, Workstation | Nothing |
Sends and receives messages transmitted by administrators or by the Alerter service. | |||
36. | Net Logon | Workstation | Nothing |
Supports pass-through authentication of account logon events for computers in a domain. | |||
37. | NetMeeting Remote Desktop Sharing | Nothing | Nothing |
D | Allows authorized people to remotely access your Windows desktop using NetMeeting. | ||
38. | Network Connections | RPC | Nothing |
Manages objects in the Network and Dial-Up Connections folder, in which you can view both local area network and remote connections. | |||
38. | Network DDE | Network DDE DSDM | ClipBook |
Provides network transport and security for dynamic data exchange (DDE). | |||
39. | Network DDE DSDM | Nothing | Network DDE |
Manages shared dynamic data exchange and is used by Network DDE | |||
40. | NT LM Security Support Provider | Nothing | DNS Server, Windows Internet Name Service (WINS), Windows Media Unicast |
Provides security to remote procedure call (RPC) programs that use transports other than named pipes. | |||
41. | On-line Presentation Broadcast | RPC | Nothing |
NA | |||
42. | Performance Logs and Alerts | Nothing | Nothing |
Configures performance logs and alerts. | |||
43. | Service: Plug and Play | Nothing | Fax Service, Smart Card, Telephony |
Manages device installation and configuration and notifies programs of device changes. | |||
44. | Print Server for Macintosh | Nothing | Print Spooler |
Enables Macintosh users to send print jobs to a spooler on a server running Windows 2000. | |||
45. | Print Spooler | RPC | Fax Service, Print Server for Macintosh, TCP/IP Print Server |
Loads files to memory for later printing. | |||
46. | Protected Storage | RPC | IIS Admin Service |
Provides protected storage for sensitive data, such as private keys, to prevent access by unauthorized services, processes, or users. | |||
47. | QoS Admission Control (RSVP) | Nothing | Nothing |
Provides network signaling and local traffic control setup functionality for QoS-aware programs and control applets. | |||
48. | Remote Access Auto Connection Manager | Remote Access Connection Manager, Telephony | Nothing |
D | Creates a connection to a remote network whenever a program references a remote DNS or NetBIOS name or address. | ||
49. | Remote Access Connection Manager | Telephony | Internet Connection Sharing, Remote Access Auto Connection Manager |
D | Creates a network connection. | ||
50. | Remote Procedure Call (RPC) | Nothing | Com+ Event Viewer, DHCP Server, Distributed Link Tracking Client, Distributed Link Tracking Server, Distributed Transaction Coordinator, DNS Server, Fax Service, File Replication, IIS Admin Service, Indexing Service, Internet Authentication Service, IPSEC Policy Agent, Kerberos Key Distribution Center , Messenger, Network Connections, On-line Presentation Broadcast, Print Counterert Spooler, Protected Storage, Remote Storage Engine, Remote Storage File, Remote Storage Media, Remote Storage Notification, Removable Storage, Routing and Remote Access, Symantec Sytem Center Discovery Service (3rd Party), Task Scheduler, Telephony, Telnet, Terminal Services Licensing, Windows Internet Name Service (WINS), Windows Media Monitor Service, Windows Media Program Service, Windows Media Station Service, Windows Media Unicast Service |
E | Provides the endpoint mapper and other miscellaneous RPC services. | ||
51. | Remote Procedure Call (RPC) Locator | Workstation | Nothing |
D | Manages the RPC name service database. | ||
52. | Remote Registry Service | Nothing | Nothing |
D | Allows remote registry manipulation. | ||
53. | Remote Storage Engine | Event Log, RPC, Remote Storage File, Remote Storage Media, Task Scheduler | Nothing |
Coordinates the services and administrative tools used for storing infrequently used data. | |||
54. | Remote Storage File | Event Log, RPC | Remote Storage Engine |
Manages operations on remotely stored files. | |||
55. | Remote Storage Media | Event Log, RPC. Removable Storage | Remote Storage Engine |
Controls the media used to store data remotely. | |||
56. | Remote Storage Notification | Event Log, RPC | Nothing |
Notifies client about recalled data. | |||
57. | Removable Storage | RPC | Remote Storage Media |
Manages removable media, drives, and libraries. | |||
58. | Routing and Remote Access | NetBIOSGroup, RPC | Nothing |
Offers routing services to businesses in local area and wide area network environments. | |||
59. | RunAs Service | Nothing | Nothing |
D | Enables starting processes under alternate credentials. | ||
60. | Security Accounts Manager | Nothing | DHCP Server, Distributed Transaction Coordinator, Intersite Messaging, Windows Internet Name Service (WINS) |
Stores security information for local user accounts. | |||
61. | Server | Boot Information Negotiation Layer, Computer Browser, Distributed File System | Nothing |
Provides RPC support and file, print, and named pipe sharing. | |||
62. | Simple Mail Transport Protocol (SMTP) | IIS Admin Service | Nothing |
D | Transports electronic mail across the network. | ||
63. | Simple TCP/IP Services | Nothing | Nothing |
E | Supports the following TCP/IP services: Character Generator, Daytime, Discard, Echo, and Quote of the Day. | ||
64. | Single Instance Storage Groveler | Nothing | Nothing |
Scans Single Instance Storage (SIS) volumes for duplicate files, and points duplicates files to one data storage point, conserving disk space. | |||
65. | Smart Card | Plug and Play | Nothing |
Manages and controls access to a smart card inserted into a smart card reader attached to the computer. | |||
66. | Smart Card Helper | Nothing | Nothing |
Provides support for legacy smart card readers attached to the computer. | |||
67. | SNMP Service | Event Log | Nothing |
Includes agents that monitor the activity in network devices and report to the network console workstation. | |||
68. | SNMP Trap Service | Event Log | Nothing |
Receives trap messages generated by local or remote SNMP agents and forwards the messages to SNMP management programs running on this computer. | |||
69. | System Event Notification | COM+ Event System | Nothing |
Tracks system events such as Windows logon, network, and power events. Notifies COM+ Event System subscribers of these events. | |||
70. | Task Scheduler | RPC | Remote Storage Engine |
Enables a program to run at a designated time. | |||
71. | TCP/IP NetBIOS Helper Service | Nothing | Nothing |
Enables support for NetBIOS over TCP/IP (NetBT) service and NetBIOS name resolution. | |||
72. | TCP/IP Print Server | Print Spooler | Nothing |
D | Provides a TCP/IP-based printing service that uses the Line Printer protocol. | ||
73. | Telephony | Plug and Play, RPC | Fax Service, Remote Auto Access Connection Manager, Remote Access Connection Manager |
Provides Telephony API (TAPI) support for programs that control telephony devices and IP based voice connections on the local computer and, through the LAN, on servers that are also running the service. | |||
74. | Telnet | RPC | Nothing |
Allows a remote user to log on to the system and run console programs using the command line. | |||
75. | Terminal Services | Nothing | Nothing |
D | Provides a multisession environment that allows client devices to access a virtual Windows 2000 Professional desktop session and Windows-based programs running on the server. | ||
76. | Terminal Services Licensing | RPC | Nothing |
Installs a license server and provides registered client licenses when connecting to a Terminal Server. | |||
77. | Trivial FTP Daemon | Nothing | Nothing |
D | Implements the Trivial FTP Internet standard, which does not require a user name or password. Part of the Remote Installation Services. | ||
78. | Uninterruptible Power Supply | Nothing | Nothing |
Manages an uninterruptible power supply (UPS) connected to the computer. | |||
79. | Utility Manager | Nothing | Nothing |
Starts and configures accessibility tools from one window. | |||
80. | Windows Installer | Nothing | Nothing |
Installs, repairs and removes software according to instructions contained in .MSI files. | |||
81. | Windows Internet Name Service (WINS) | NT LM Security Provider, RPC, Security Accounts Manager | Nothing |
O | Provides a NetBIOS name service for TCP/IP clients that have to register and resolve NetBIOS-type names. *NB: If we remove Netbeui (recommended) as a LAN protocol we must use WINS to allow for NetBIOS over TCP/IP support - set in Network Properties > Internet Protocol (TCP/IP) > Properties > Advanced > WINS (tab). - There is no added WINS server maintenace overhead, such as having to push LMHOSTS files accross the LAN. |
||
82. | Windows Management Instrumentation | RPC | Nothing |
Provides system management information. | |||
82. | Windows Management Instrumentation Driver Extensions | Nothing | Nothing |
Provides systems management information to and from drivers. | |||
83. | Windows Media Monitor Service | RPC | Nothing |
Provides services to monitor client and server connections to the Windows Media services | |||
84. | Windows Media Program Service | RPC, Windows Media Station Service | Nothing |
Used to group Windows Media streams into a sequential program for the Windows Media Station Service. | |||
85. | Windows Media Station Service | RPC | Windows Media Program Service |
Provides multicasting and distribution services for streaming Windows Media content. | |||
86. | Windows Media Unicast Service | NT LM Security Support Service, RPC | Nothing |
Provides Windows Media streaming content on-demand to networked clients | |||
87. | Windows Time | Nothing | Nothing |
E | Sets the computer clock. | ||
88. | Workstation | Nothing | Alerter, Computer Browser, Distributed File System, File Server for Macintosh, Messenger, Net Logon, RPC |
E | Provides network connections and communications. | ||
89. | World Wide Web Publishing Service | IIS Admin Service | Nothing |
E | Provides Web connectivity and administration through the Internet Information Services snap-in. |
IV. Miscellaneous Issues:
Obviously it is advisable to be very strict about scanning any floppy or other writable media before reading its contents. People get lazy about this but should remain vigilant.
Don't be fooled by CDROMs. They may inadvertently be harboring viruses.