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For those of us that are still using Windows XP one of the easiest ways for crackers to exploit holes in your
system is through open services.
And lately, viruses have been masquerading as services listed in the
Task Manager, making them harder to detect, clean and prevent.
When you audit and close unused services, in addition to security
benefits, you receive performance enhancement because stagnant
programs aren't taking up available resources.
Besides, a full security audit of your service can reveal some
interesting details about your machine.
Windows XP comes with only two services that require open access
to an external interface for normal operation: Terminal Services, or
Remote Desktop Connection, and the Remote Access Service for
answering dial-in calls.
Follow these instructions to manage services on your computer:
1.
Right-click My Computer, and choose Manage.
2.
Expand the Services & Applications tab, and select Services.
3.
Double-click a service.
4.
Under Startup Type, select Manual to disable a service from
automatically starting when the computer boots up. Click the Stop
button to stop the service if it's already running.
The following services ship with Windows XP. The list is not
complete, but it includes the recommended state that each service
shown should be in on your computer, assuming normal office
functions are performed on the machine.
On this list you'll see the name of the service, followed by a short
description and my recommendation regarding the state of the
service.
-
Alerter: Raises
administrative alerts for selected users and computers.
Disabled.
-
Application
Layer Gateway Service: Required if you use Internet Connection
Sharing (ICS) or XP's included Internet Connection Firewall to
connect to the Internet.
Automatic if using ICS; Disabled if not.
-
Application
Management: Used to assign, publish and remove software through
Group Policy. Disabled unless you participate in an
Active Directory domain.
-
Automatic
Updates Service: Checks to see if any critical updates are
available for download. Requires Cryptographic to be running.
Automatic if you don't wish to use Windows Update manually.
-
Background
Intelligent Transfer Service: Used by Windows Update to transfer
data in the background using otherwise idle available network
bandwidth. Disabled.
-
ClipBook:
Enables the ClipBook Viewer to create and share data to be
viewed by remote computers. Disabled.
-
COM+ Event
System: Provides Automatic distribution of events to subscribing
programmatic components. Disabled.
-
COM+ System
Application: Provides Automatic distribution of events to
subscribing programmatic components. Disabled.
-
Computer
Browser: Maintains an up-to-date list of computers on your
network and supplies the list to programs that request it.
Disabled.
-
Cryptographic
Services: Confirms signatures of Windows files. Required for
Windows Update to function in manual and Automatic mode and
required for Windows Media Player as well. Automatic.
-
DHCP Client:
Manages network configuration by registering and updating IP
addresses and DNS server information. Automatic if
required; Disabled if not.
-
Distributed Link
Tracking Client: Maintains links between the NTFS file system
files within a computer or across computers in a network domain.
Disabled.
-
Distributed
Transaction Coordinator: Coordinates transactions that are
distributed across multiple computer systems and/or resource
managers, such as databases, message queues, file systems or
other transaction-protected resource managers. Disabled.
-
DNS Client:
Resolves and caches DNS (Domain Name System) names. The DNS
client service must be running on every computer that will
perform DNS name resolution. Automatic.
-
Error Reporting
Service: Calls home to Microsoft when errors occur. Disabled.
-
Event Log: Logs
event messages issued by programs and Windows. This can be
useful in diagnosing problems. Automatic.
-
Fax Service:
Enables you to send and receive faxes. Disabling this service
will render the computer unable to send or receive faxes.
Disabled; or don't install from distribution media.
-
Telephony:
Provides Java 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. Disabled unless required.
-
FTP Publishing
Service: Not available on Windows XP Home. Not installed by
default on Windows XP Pro. Enables FTP service. Disabled,
or don't install from distribution media.
-
Help and
Support: Required for Microsoft's online help documents.
Automatic.
-
Human Interface
Device Access: If all your devices function, then disable it.
Disabled.
-
IIS Admin: Not
available on Windows XP Home. Not installed by default on
Windows XP Pro. Allows administration of Internet Information
Services (IIS). Disabled, or don't install from
distribution media.
-
IMAPI CD-Burning
COM Service: Used for the "drag-and-drop" CD-burn capability.
You'll need this service to burn CDs. Automatic.
-
Indexing
Service: Indexes contents and properties of files on local and
remote computers and provides rapid access to files through a
flexible querying language. Disabled.
-
Internet
Connection Firewall and Internet Connection Sharing: Provides
network address translation (NAT), addressing and name
resolution services for all computers on your home or
small-office network through a dial-up or broadband connection.
Automatic if sharing connection, Disabled if not
required.
-
IPsec Services:
Manages IP security (IPsec) policy, starts the Internet Key
Exchange (IKE) and coordinates IPsec policy settings with the IP
security driver. Disabled.
-
Logical Disk
Manager: Watches Plug and Play events for new drives to be
detected and passes volume and/or disk information to the
Logical Disk Manager Administrative Service to be configured. If
Disabled, the Disk Management snap-in display will not
change when disks are added or removed. Manual.
-
Logical Disk
Manager Administrative Service: See previous item's description.
Manual.
-
Message Queuing:
A messaging infrastructure and development tool for creating
distributed messaging applications for Windows. Disabled;
or don't install from distribution media.
-
Message Queuing
Triggers: Required only if you use Message Queuing Service.
Disabled; or don't install from distribution media.
-
Messenger: Sends
and receives messages to or from users and computers, or those
transmitted by administrators or by the Alerter Service.
Disabled.
-
Microsoft
Software Shadow Copy Provider: Used in conjunction with the
Volume Shadow Copy Service. Microsoft Backup uses these
services. Enabled.
-
NetMeeting
Remote Desktop Sharing: Allows authorized users to remotely
access your Windows desktop from another PC over a corporate
intranet. Disabled.
-
Network
Connections: Manages objects in the Network and Dial-Up
Connections folder, where you can view both network and remote
connections. Automatic.
-
Network DDE:
Useless service unless you use remote ClipBook. Disabled.
-
Network DDE DSDM:
See previous item's description. Disabled.
-
Network Location
Awareness (NLA): Required for use with the Internet Connection
Sharing Service (server only). Disabled, unless running
ICS or ICF.
-
NTLM Security
Support Provider: Enables users to log on to the network using
the NTLM Authentication Protocol. If this service is stopped,
users will be unable to log on to the domain and access
services. NTLM is used mostly by Windows versions prior to
Windows 2000. Automatic.
-
Performance Logs
and Alerts: Configures performance logs and alerts. Disabled.
-
Plug and Play:
Enables a computer to recognize and adapt to hardware changes
with little or no user input. Automatic.
-
Portable Media
Serial Number: Retrieves serial numbers from portable music
players connected to your computer. Disabled.
-
Print Spooler:
Queues and manages print jobs locally and remotely. If you don't
have a printer attached, then disable. Automatic.
-
Protected
Storage: Provides protected storage for sensitive data, such as
private keys, to prevent access by unauthorized service
processes or users. Disabled.
-
QoS RSVP:
Provides network signaling and local traffic-control
functionality. Disabled, unless required by your network
administrator.
-
Remote Access
Auto Connection Manager: Creates a connection to a remote
network whenever a program references a remote DNS or NetBIOS
name or address. Disabled.
-
Remote Access
Connection Manager: Creates a network connection. Automatic if
using Dial-Up Networking; Disabled otherwise.
-
Remote Desktop
Help Session Manager: Manages and controls Remote Assistance.
Disabled.
-
Remote Procedure
Call (RPC): Provides the endpoint mapper and other miscellaneous
RPC services. Automatic.
-
Remote Procedure
Call Locator: Manages the RPC name service database. Disabled.
-
Remote Registry
Service: Not available on Windows XP Home. Allows users to
connect to a remote Registry and read and/or write keys to it --
providing they have the required permissions. Disabled.
-
Removable
Storage: Manages removable media drives and libraries. This
service maintains a catalog of identifying information for
removable media used by a system, including tapes, CDs and so
on. Disabled.
-
RIP (Routing
Information Protocol) Listener: Not installed by default.
Disabled; or don't install from distribution media.
-
Routing and
Remote Access: Offers routing services in local area and wide
area network environments. Disabled; or don't install
from distribution media.
-
Secondary Logon:
Allows you to run specific tools and programs with different
permissions than your current logon provides. Automatic.
-
Security
Accounts Manager: Startup of this service signals other services
that the Security Accounts Manager subsystem is ready to accept
requests. Automatic.
-
Server: Provides
RPC support and file print and named pipe sharing over the
network. The Server Service lets you share your local resources
(such as disks and printers) so that other users on the network
can access them. Automatic if you're sharing files;
Disabled if not.
-
Shell Hardware
Detection: Used for the auto play of devices like memory cards,
some CD drives and so on. Disabled unless required.
-
Simple Mail
Transport Protocol (SMTP): Transports e-mail across the network.
Disabled; or don't install from distribution media.
-
Simple TCP/IP
Services: Implements support for a number of IP protocols.
Disabled; or don't install from distribution media.
-
Smart Card:
Manages and controls access to a smart card inserted into a
smart card reader attached to the computer. Disabled
unless using a smart card reader.
-
Smart Card
Helper: Provides support for earlier smart card readers attached
to the computer. Disabled unless using a smart card
reader.
-
SNMP Service:
Allows Simple Network Management Protocol (SNMP) requests to be
serviced by the local computer. Disabled; or don't
install from distribution media.
-
SNMP Trap
Service: Receives trap messages generated by local or remote
SNMP agents and forwards the messages to SNMP management
programs running on the computer. Disabled; or don't
install from distribution media.
-
SSDP Discovery:
Used to locate UPnP (Universal Plug and Play) devices on your
home network. Disabled.
-
System Event
Notification: Tracks system events such as Windows logon network
and power events. Disabled.
-
System Restore
Service: Creates system snapshots or restore points for
returning to at a later time. Disabled.
-
Task Scheduler:
Enables a program to run at a designated time. Disabled
unless absolutely required.
-
TCP/IP NetBIOS
Helper: Enables support for NetBIOS over TCP/IP (NetBT) service
and NetBIOS name resolution. Only required if you need to share
files with others. Disabled unless sharing is enabled.
-
TCP/IP Printer
Server: Used for setting up a local Unix print server.
Disabled, or don't install from distribution media.
-
Telephony:
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. Disabled.
-
Telnet: Allows a
remote user to log on to the system and run console programs by
using the command line. Disabled, or don't install from
distribution media.
-
Terminal
Services: Provides a multi-session environment that allows client
devices to access a virtual Windows 2000 Professional desktop
session and Windows-based programs running on the server.
Disabled, or don't install from distribution media.
-
Themes: Used to
display all those new XP themes and colors on your desktop. Lots
of space needed. Automatic or manual, depending on
your preferences.
-
Uninterruptible
Power Supply (UPS) manages communications with a UPS connected
to the computer by a serial port. Disabled unless using a
UPS.
-
Universal Plug
and Play Device Host. Used in conjunction with SSDP Discovery
Service, it detects and configures UPnP devices on your home
network. Disabled.
-
Upload Manager:
As with BITS, this service manages file transfers between
clients and servers on the network. This service is not required
for basic File and Print sharing. Disabled.
-
Volume Shadow
Copy: Used in conjunction with the Microsoft Software Shadow
Copy Provider Service. Microsoft Backup uses these services.
Disabled.
-
WebClient:
Disable this for security reasons. Disabled.
-
Windows Audio:
Used to produce audio. Automatic.
-
Windows Image
Acquisition (WIA): Used for some scanners and cameras. If, after
disabling this service, your scanner or camera fails to function
properly, enable this service. Disabled.
-
Windows
Installer: Installs, repairs or removes software according to
instructions contained in MSI files provided with the
applications. Manual.
-
Windows
Management Instrumentation (WMI): Provides system management
information. WMI is an infrastructure for building management
applications and instrumentation shipped as an integral part of
the current generation of Microsoft operating systems.
Automatic.
-
Windows
Management Instrumentation Driver Extension: Tracks all of the
drivers that have registered WMI information to publish.
Manual.
-
Windows Time:
Sets the computer clock. W32Time maintains date and time
synchronization on all computers running on a Windows network.
Automatic.
-
Wireless Zero
Configuration: Automatic configuration for wireless network
devices. Disabled.
-
WMI Performance
Adapter: Optimizes the speed of WMI queries. Disabled.
-
Workstation:
Provides network connections and communications. If this service
is turned off, no network connections can be made to remote
computers using Microsoft Networks. Automatic.
-
World Wide Web
Publishing: Provides HTTP services for applications on the
Windows platform. Disabled; or don't install from
distribution media.
As you can see from the list, you don't need very much to keep
your Windows XP installation functioning, at least in a non domain
environment.
Most of the enabled services just pose an unfavorable security risk
compared to the reward, bring little or no benefit, consume
resources and can be safely turned off.
While disabling unnecessary services is an excellent and fundamental
step to hardening Windows, there are some other necessary items to
accomplish to further secure the services that remain and any
services that you may add in the future.
Peruse the following list of best practices and
consider implementing them.
-
Give strong
passwords to service accounts. When you install applications
that require services to run, you are typically given the option
to choose an account under which the service is to be run. Use
15+ character passwords, and remember that you must set these
passwords both in Active Directory Users and Computers or
Computer Management (depending on your operating environment)
and in the Log-On tab of the service's property sheet.
-
Never let users
log on using service accounts. This particularly applies to the
Administrator account -- never assign the Administrator account
to a service, and never distribute any service account name and
password to any users. There is absolutely no reason to do so,
and if users can access systems in these contexts, they can
wreak more havoc than you could imagine. Just don't do it.
-
Do not allow
network access to service accounts. For one, this means don't
create domain accounts for services. Wherever possible, use a
local account on the server where the service is located. Also,
check the "Deny Access to this Computer from the Network" right
within the service account's property sheet to eliminate network
access for that account.
-
Use accounts of
least privilege for service accounts. Windows XP includes a
great set of built-in accounts, collectively called the Network
Service and Local Service. They are specifically designed to be
used for services that require different amounts of network
connectivity. Use these where possible to decrease the attack
surface of services.
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