10 steps to harden windows server 2008
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10 steps to harden Windows Server 2008
Ever since it’s debut, Microsoft Windows 2008 Server has awed security and systems administrators
with its complex and innovative features. With threats becoming each day more immanent and efficient,
security system administrators face the tedious task of protecting Microsoft’s new giant. In this article we
compiled some of the industries best practices such as NIST to show you some of the features and ways
to reduce your windows 2008 servers’ exposure.
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1. Configure a security policy
The first step in securing the 2008 server is to configure a security policy. In order to configure a
security policy, you will need to use the SCW (Security Configuration Wizard), which can be installed
through “add and remove windows components”. The SCW detects ports and services, and configures
registry and audit settings according to the servers “role” or installed applications. The SCW uses a set of
XML templates which can easily be deployed and managed. The version of SCW in Windows
Server 2008 includes over 200 server role configurations and security settings than the version of SCW in
Windows Server 2003. Also, by using the version of SCW in Windows Server 2008, you can:
* Disable unneeded services based on the server role.
* Remove unused firewall rules and constrain existing firewall rules.
* Define restricted audit policies.
The server’s operating system will be changed according to the profile or template
selected. Administrators can create custom profiles and deploy them using a set o XML files.
2. Disable or delete unnecessary accounts, ports and services
Attackers often gain access to servers through unused or not configured ports and services. To
limit entry points, server hardening includes blocking unused ports and protocols as well as disabling
services that are not required. Although this can be done as seen above using the SCW, the server
administrator would need to double check to see if all the services are configured properly and that only
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the necessary ports are open. During the installation of the 2008 server, by default, three local user
accounts are automatically created: the Administrator, Guest and Help Assistant. The Administrator
account bears high privileges, and requires special diligence. As a security best practice the administrator
account should be disabled or renamed to make it more difficult for an attacker to gain access. Both
Guest and Help Assistant accounts provide an easy target for attackers which exploited this vulnerability
before on the earlier Windows Server 2003. These accounts should be disabled at all times.
3. Uninstall Unnecessary Applications
Remember, your server is a vital part of your network and services that you provide. The number
of applications installed on these servers should be role related and set to a minimum. It is a good idea to
test these applications out in a separate environment before deploying them on the production network.
Some applications make use of service backdoors, which can sometimes compromise the overall security
of the server. After installing each application, make sure that you double check to see if the application
created any firewall exception or created a service user account.
* Belarc Advisor : The Belarc Advisor “builds a detailed profile of your installed
software and hardware, missing Microsoft hot fixes, anti-virus status, and
displays the results in your Web browser.” This tool is free for personal use.
Commercial, government, and non-profit organizations should look at their other
products which include many more features for managing security on multiple
computers.
* Micr os oft SysInternal Tools : Microsoft provides a set of tools which can be
used to monitor the server’s activity. These tools include: REGMON, FILEMON,
Process Explorer, Root Kit Revealer. These tools are great for understanding
what a certain application or software does “under the sheets”.
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4. Configure the windows 2008 Firewall
Windows 2008 server comes with a phenomenal built in firewall called the Windows Firewall with
Advanced Security. As a security best practice, all servers should have its own host based firewall. This
firewall needs to be double checked to see if there are no unnecessary rules or exceptions. I have
outlined some of the new features that the Windows Server 2008 provides.
* GUI interface: a MMC snap-in available for the Advanced Firewall
Configuration.
* Bi-directional filtering: the firewall now filters outbound traffic as well as
inbound traffic.
* IPSEC operability: now the firewall rules and IPSEC encryption configurations
are integrated into one interface.
* Advanced Rules configuration: you can create firewall rules using Windows
Active Directory objects, source & destination IP addresses and protocols.
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5. Configure Auditing
One of the most significant changes on Windows Server 2008 auditing is that now you can not
only audit who and what attribute was changed but also what the new and old value was.
This is significant because you can now tell why it was changed and if something doesn’t look right you’re
able to easily find what it should be restored to.
Another significant change is that in the past Server versions you were only able to turn auditing
policy on or off for the entire Active Directory structure. In Windows Server 2008 the auditing policy is
more granular.
As a security best practice, the following events should be logged and audited on the Windows Server
2008.
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* Audit account logon events
* Audit account management
* Audit directory service access
* Audit logon events
* Audit object access
* Audit policy change
* Audit privilege use
* Audit process tracking
* Audit system events
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Most log events on the event viewer have registered incident ID numbers; these numbers can be used to
troubleshoot the server. http://www.eventid.net/ is a good site which aids security and system
administrators in finding out what actually happened with their servers. A best practice would also be to
forward these audit logs to a centralized server as required by PCI DSS 10.5.3 and other industry
standards. Windows Server 2008 offers a native log subscription feature which forwards all system and
security audit logs to a centralized server.
6. Disable unnecessary shares
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Unnecessary shares pose a great threat to vital servers. After a server or application deployment,
system and security administrators should check to see if the server has any unnecessary shares. This
can be done using the following command:
Net Share
This will display a list of all shares on the server. If there is a need to use a share, system and security
administrators should configure the share as a hidden share and harden all NTFS and Share
permissions.
C:\Documents and Settings>net share
Share name Resource Remark
-------------------------------------------------------------------------------
ADMIN$ C:\WINDOWS Remote Admin
C$ C:\ Default share
IPC$ Remote IPC
In order to create a hidden share, put a $ sign after the share name. The share will still be accessible;
however it will not be easily listed through the network. Example:
Accounting$
7. Configure Encryption on 2008 server
According to industry best practices, such as HIPAA and GLBA require that certain servers
which host sensitive information should make use of encryption. Windows Server 2008 provides a built in
whole disk encryption feature called BitLocker Drive Encryption (BitLocker). BitLocker protects the
operating system and data stored on the disk. In Windows Server 2008, BitLocker is an optional
component that must be installed before it can be used. To install BitLocker, select it in Server Manager
or type the following at a command prompt:
ServerManagerCmd -install BitLocker –restart
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8. Updates & Hot fixes
Updates and hot fixes are key elements when hardening a server. System and security
administrators should be constantly updating and patching their servers against zero day vulnerabilities.
These patches are not limited to the operating system, but also any application which is hosted on them.
Administrators should periodically check the vendor’s websites for updates. Windows Server 2008 offers
a set of tools which helps administrator update and patch their servers.
* WSUS: Windows Server Update Services (WSUS) provides a software update service
for Microsoft Windows operating systems and other Microsoft software. By using
Windows Server Update Services, administrators can manage the distribution of
Microsoft hot fixes and updates released through Automatic Updates to computers in a
corporate environment. WSUS helps administrators track the “update health” of each
individual server.
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* MBSA: Microsoft Baseline Security Analyzer (MBSA) is an easy-to-use tool designed
for the IT professional that helps small- and medium-sized businesses determine their
security state in accordance with Microsoft security recommendations and offers specific
remediation guidance. Improve your security management process by using MBSA to
detect common security misconfigurations and missing security updates on your
computer systems.
9. Anti Virus & NAP
Anti Virus software is also a crucial step for hardening a server. Windows Server 2008 offers a
set of tools which can help combat unauthorized network access and malicious code execution.
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Windows Server 2008 offers a Network Access Protection (NAP), which helps administrators to
isolate viruses from spreading out into the network. Windows server 2008 NAP uses a set of policies
which cleans the affected machines and when they are healthy, permits them access to parts of your
production network.
NAP consists of client server technology which scans and identifies machines that don't have the
latest virus signatures, service packs or security patches. Some of the key functions of a Windows Server
2008 NAP server includes:
* Validating Machines : The mission of NAP is to preserve the integrity
of the network by allowing only healthy machines to have IP addresses.
* Restricting Network Access : Computers or servers which don't meet
the established policy standards can be restricted to a “quarantine”
subnet where they would later be remediate the security issues.
* Fixing Unhealthy Machines : Windows Server 2008 NAP has the
ability to direct hosts to a remediation server, where the latest antivirus
signatures and patches are deployed through SMS packages.
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10. Least Privilege
The concept of least privilege has been adopted by many of today’s industry standards. A
hardened server needs to have all its access reduced to a bare operational minimum. Most of the known
security breaches are often caused by elevated privileges bared by accounts. Server services should not
be configured using enterprise wide administrator accounts. Windows Server 2008 has a couple of tools
which can aid administrator to grant or revoke access to specific sections of the server.
* Script Logic’s Cloak : Script Logic Cloak is a product which enhances the Windows NT File
System (NTFS) by providing increased security, more accurate audits and a vastly streamlined
experience for users of the network.
* PolicyMaker Application Security: PolicyMaker is an add-on for the Group Policy
Management Console (GPMC). This tool allows administrators to adjust application privilege
levels to the lowest possible point in order to limit damages stemming from network attacks or
user error. The ability to control security at such a granular level also helps organizations comply
with regulatory mandates such as the Sarbanes-Oxley, HIPAA and Gramm-Leach-Bliley acts.
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On the next Post I will go over each feature here described, creating a setp by step guideline on how to
configure and install the following features:
* SCW
* Bitlocker
* NAP
* Windows Firewall with Advanced Security
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