Hi All,

The below will be of help to understand how to secure the active directory
or key areas to look for during audit of systems / network.

When a security professional is asked what repositories are most used to
gain access to the infrastructure services and applications, one of two
answers is almost always given: LDAP or Active Directory.

While the first is an international standard repository supported by almost
all of the directory vendors in the marketplace, Active Directory has almost
as large of an enterprise deployment footprint as all of the LDAP vendors
combined (even though it is supplied by a single vendor, Microsoft).  From
its initial use as a tool for authenticating a few interconnected PCs, it
has grown into the premier enterprise repository.  With the level of
complexity needed for today's enterprise repository deployments, IT managers
spend hours and hours on design and support activities to ensure the
features and functions of Active Directory meet the needs of the
organization.  But some IT managers overlook the most important task:
securing their Active Directory itself.

Active Directory contains the keys to the kingdom when it comes to group and
user account information.  In most cases, if an organization's Active
Directory deployment were to experience a catastrophic event, no one within
the organization would be able to access the services they need to perform
their duties.

So what's the best way to determine if the security of an Active Directory
infrastructure is sufficient?  A periodic Active Directory security audit is
required to ensure that Active Directory is being properly managed and
protected.  But audit personnel must understand what coverage areas are
important for the security of an Active Directory deployment and what to
look for.  The list below will help in understanding how to ensure Active
Directory security:
*
Policy and architecture* - Active Directory, like any enterprise service,
must have a long-term management plan.  Auditors should look for
well-documented policies and architectures that define what information is
owned by Active Directory, who is allowed to access it, what Active
Directory's functional role is within the organization and how architectural
changes should be made and documented.

*Physical placement *- At the lowest level, ensuring that Active Directory
servers and their domain controllers are secure means ensuring that they are
located in physically secure spaces.  Whether in professional data centers
or locked communications closets, Active Directory servers should always be
protected against physical theft.  Finding Active Directory servers under
desks or in open, unsecured spaces may be an indicator that the
organization's deployment of Active Directory is insufficient to secure it.

*Distributed deployment* - Due to the criticality of the role that Active
Directory plays in allowing access to systems and services, Active Directory
repositories should be distributed across the organization. While an
architecture project should be in place to determine where the Active
Directory repositories should be distributed, some good positions to
consider are geographic locations with slow wide area network links,
physical areas of large populations of users, and an area close to identity
access services that use Active Directory for authentication/authorization.
Also, a good replication service must be in place between the distributed
servers to ensure that denial-of-service (DoS) attacks will have minimal
impact.  Placing Active Directory services close to the users who depend on
them for access ensures that network and power outages will minimize
downtime.
*
Administrative access* - Organizations should take advantage of Active
Directory's multi-level administrative access services to tailor
administrative functions to administrative privileges.  Auditors should
ensure that full administrative access is limited to a small number of
administrators who are responsible for server-to-server interoperation and
configuration, along with schema management.  Personnel responsible for a
subset of administrative functions, such as help desk personnel who reset
passwords, should be given only the ability to perform their functions
without any additional administrative access.  And when it comes to
creation, deletion and updating of accounts, automated tools, like a
provisioning system, should do the job in order to minimize manual errors
and guarantee protection of sensitive account information.

*Active Directory groups *- Active Directory groups are used to manage
access to services at a macro level.  By assigning a user to a group, the
user automatically inherits the group's access privileges.  Active Directory
group management originally started out organically -- groups were created
on the fly with little documentation and few controls -- and that led to a
lack of understanding of the groups' original purposes by later
administrators.  This caused Active Directory groups to proliferate at a
speed that made them hard to manage; this is one of the key areas for
auditors to explore. In auditing Active Directory groups, auditors should
look for clear, well-defined processes for the management of these groups.
Also, documentation should be completed on who the group owner is, any
projects the groups might have been created for, how long the groups are
valid, what access the groups grant, and any other Active Directory groups
related to the group in question that may be used for access.

*Schema configuration* - Active Directory stores information in a
spanning-tree directory schema.  Users and groups are allowed access based
on their placement in the hierarchy and the access control lists (ACL) for
the various containers, as well as objects for access rights (read, write,
execute, delete).  Auditors should review the layout of the Active Directory
schema, and the associated ACLs, to ensure they are configured to provide
sufficient separation and protection of information from other groups or
users stored within Active Directory.

*Strong automated account management* - As stated above, most organizations
have moved to automated provisioning tools to manage Active Directory
accounts.  But just because the tools are automated doesn't mean they're
automated well.  Auditors should look for well-defined processes for account
requests and well-thought-out rules within the provisioning tool that ensure
correct privileges. Also, accesses should be granted along with correct
workflows when access requires the user's manager or resource owner to
approve the access.  In addition, auditors should ensure that any accounts
not recently accessed, or accounts no longer needed, are disabled or removed
in a timely manner.  Finally, to ensure the right access privileges are
still in place, the organization should have a "recertification" process
wherein managers or administrators are periodically required to certify that
the accesses for the persons under their responsibility correspond correctly
to the users' responsibilities and the functions they perform.

*Active Directory integration* - While the list above outlines a number of
Active Directory-specific requirements for securing the repository, the fact
is that many legacy application and servers still can't directly access
Active Directory and must be synchronized with it.  This involves extracting
information from Active Directory and electronically forwarding it to other
applications and servers, where the information is then stored locally on
the receiving system.  Auditors should check to see if data transfers from
Active Directory are still required by inquiring whether new methods are
available to allow these applications and servers to directly connect to
Active Directory and not copy its information.  Auditors should also ensure
that the Active Directory information in the local application or server has
the same level of access controls as it has in Active Directory.  Finally,
auditors should ensure that the Active Directory information isn't forwarded
on to other applications or servers from the receiving systems to make
certain that the information can be tracked to all the servers and
applications which consume them.

Active Directory has evolved from department-level PC control to a fully
functioning enterprise directory.  While initially Active Directory
deployments were below the radar of most auditors, due to the ever-evolving
role of controlling access, Active Directory is now clearly in the sights of
organizational security and audit teams.  Thus, while scrutiny of Active
Directory security has increased many times over, it is fully justified.
Due to the important access services it provides, organizations don't want
the keys to the kingdom to be left unprotected.


------------------------------

*About the author: Randall Gamby is an enterprise security architect for a
Fortune 500 insurance and finance company who has worked in the security
industry for more than 20 years. He specializes in security/identity
management strategies, methodologies and architectures.*


Regards
T. Amardeep

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