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Locking Down a Hitachi ID Password Manager Server

arrowAbstract
Organizations that are either considering deployment of Hitachi ID Password Manager or have already deployed it need to understand how to secure the Password Manager server. Password Manager is a sensitive part of an organization's IT infrastructure and consequently must be defended by strong security measures.

This document is intended to form the basis of a "best practices" guide for securing a Password Manager server. The objective of a secure Password Manager server is to have a reliable, high availability server which is difficult or impossible for users and intruders to compromise.

Introduction

Organizations that are either considering deployment of Password Manager or have already deployed it need to understand how to secure the Password Manager server. Password Manager is a sensitive part of an organization's I.T. infrastructure and consequently must be defended by strong security measures.

Password Manager houses sensitive data, which may include:

  • Administrator credentials to target systems, which the Password Manager server uses to attach to target systems and reset user passwords.
  • Support staff passwords, which may be used to log into user support screens in Password Manager.
  • Personal user data, which may be managed by Password Manager and used to authenticate users when they need to access a self-service function, and have forgotten or locked out their password.

It is important to protect both the Password Manager server itself and the data it contains.

The remainder of this document is organized as follows:

  • Basic precautions

    Some common-sense security precuations.

  • Operating system

    How to configure a secure Windows server operating system for use with Password Manager.

  • Web server

    How to select and configure a web server.

  • Communication defenses

    How to protect the data transmitted into and out of each Password Manager server.

  • Data protection

    How the data stored on each Password Manager server is protected.

  • Auditing

    Why auditing is important.

  • Physical Security

    Suggestions on how to control the physical access to the Password Manager server.

  • Conclusions

Basic precautions

Some of the most effective security measures are common sense:

  1. Use a single-purpose server for Password Manager. Sharing this server with other applications introduces more complexity and more administrators, each of which carries its own incremental risk.

  2. Use strong passwords for every administrative account on the server.

  3. Maintain a current, well-patched operating system on the Password Manager server. This eliminates well-known bugs that have already been addressed by the vendor (Microsoft).

  4. Keep the Password Manager server in a physically secure location.

  5. Do not leave a login session open and unattended on the Password Manager server's console.

  6. Place the Password Manager server on your internal network, rather than on the Internet, if this is at all possible in your environment.

    If required, you can still expose the Password Manager web UI to the Extranet using a reverse web proxy, such as Apache, or using a "shadow instance" program available at no extra charge from Hitachi ID Systems.

Operating system

The first step in configuring a secure Password Manager server is to harden its operating system.

Hitachi ID Systems suggests that Password Manager be installed on the Windows 2003 server operating system. The following are suggestions on how to lock down this operating system.

Authentication into the server

Since the Password Manager server contains sensitive information (please see [link] for how this information is stored), it makes sense to limit the number of users who can access its files.

Domain membership

One way to limit the number of users who can access the Password Manager server is to remove it from any Windows / Active Directory domains. When the Password Manager server is not a member of any domain, domain administrators are prevented from using their Windows credentials to attempt to compromise privileged credentials on other systems with which Password Manager has been integrated.

Ensuring that the Password Manager server is not a domain member also reduces the risk of lockouts due to concurrent domain logins by the Password Manager server - some by the Password Manager software, and others by an administrator interactively logged into the server's console.

Accounts

The Password Manager setup program creates one local user on the Password Manager server, typically called psadmin.

The account is, by default, a member of the local Administrators group. It is the only account needed by Password Manager. We recommend removing unused accounts, leaving just:

  • psadmin - The Password Manager service account.
  • One account to be used by the Password Manager administrator to log into the server's console.

    Note:

    Use the DENY NETWORK LOGON feature in the local security policy to protect the Administrator account against remote access attempts using brute force password attacks.

  • If (and only if) required, one account to run an FTP service.

If you need other accounts on the Password Manager server, then we recommend the following:

  • Remove all guest account and "Everyone" access to resources.
  • Do not increase the default level of access for the default USERS group.
  • Do not assign files/directories to the EVERYONE group.
  • Limit the number of administrator-level accounts needed to manage the system. As stated above, the Password Manager server only requires one administrator-level account.
  • Remove the terminal services user account TsInternetUser if it is not needed.

Additionally, a regular review of accounts, groups and group memberships should be carried out, to ensure that access permissions are appropriate.

Securing services

An important way to secure a server on any platform is to reduce the amount of software that it runs. This eliminates potential sources of software bugs that could be exploited to violate the server's security.

The following services, at most, are needed on the Password Manager server:

  • DNS Client - Required to resolve host names
  • Event Log - Core O.S. component
  • IIS Admin Service - Only required if IIS is used
  • IPSEC Policy Agent - Core O.S. component
  • Logical DiskManager - Core O.S. component
  • Network Connections - Required to manage network interfaces
  • Plug and Play - Hardware support
  • Protected Storage - Core O.S. component
  • Remote Procedure Call (RPC) - Core O.S. component
  • Removable Storage - Required to open CD-ROM drives
  • RunAs Service - Core O.S. security component
  • Security Accounts Manager - Core O.S. security component
  • TCP/IP NetBIOS Helper Service - Only required if directly managing Windows passwords
  • Workstation - Only required if directly managing Windows passwords
  • World Wide Web Publishing Service - Only required if IIS is used

If additional services are required during implementation, then Hitachi ID Systems will notify Hitachi ID Systems customer.

All other services should be disabled unless there is some specific reason (not related to Password Manager) to enable them. Once you have identified a minimum set of services for your server, save the list. Check which services are running after applying service packs and other operating system updates, and disable services as required to return to your original list.

Network and session security

Packet filtering

The Password Manager server can also take advantage of simple packet filtering services in Windows 2003, to block all inbound connections other than those to the web service, as shown in the figure below:

figure

Open ports are an exploitable means of system entry. By limiting the number of open ports, you effectively reduce the number of potential entry points into the server.

A hardened Password Manager server can be port scanned to identify available services. Following is a typical port scan result:

      delli:/data/idan/vmware/win2ksrv# nmap -sT 192.168.100.8

      Starting nmap V. 2.54BETA31 ( www.insecure.org/nmap/ )
      Interesting ports on  (192.168.100.8):
      (The 1551 ports scanned but not shown below are in state: closed)
      Port       State       Service
      80/tcp     open        http
      443/tcp    open        https


      Nmap run completed -- 1 IP address (1 host up) scanned in 1 second
      delli:/data/idan/vmware/win2ksrv# nmap -sU 192.168.100.8

      Starting nmap V. 2.54BETA31 ( www.insecure.org/nmap/ )
      All 1459 scanned ports on  (192.168.100.8) are: filtered

      Nmap run completed -- 1 IP address (1 host up) scanned in 91 seconds

The process table on the same server looks like this:

figure

Note: VMWare entries in the figure reflect the fact that this sample was taken from a VMWare virtual PC.

This server was running with just the mandatory services described earlier.

Harden the IP stack

Enable the following TCP/IP registry settings as shown below to make the Password Manager server resistant to denial of service (DOS) attacks:

Note:

Some of the settings may cause some applications to fail. Be sure to test all settings before implementing.

             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\SynAttackProtect
    
    Type: REG_DWORD
    Value: 1 - reduced re-transmission retries and delayed RCE (route cache entry) creation of the TcpMaxHalfOpen and TcpMaxOpenRetried settings are satisfied (see below).
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\TcpMaxHalfOpen
    
    Type: REG_DWORD
    Value: 100 - for Windows 2000 Professional or Server Value: 500 - for Windows 2000 Advanced Server
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\TcpMaxHalfOpenRetried
    
    Type: REG_DWORD
    Value: 80 - for Windows 2000 Professional or Server Value: 400 - for Windows 2000 Advanced Server
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\TcpMaxPortsExhausted
    
    Type: REG_DWORD
    Value: 5

The following keys, not present on a default Windows server installation, are also helpful to protect against a variety of attacks against the IP stack:

             HKLM\System\CurrentControlSet\Services
                 \AFD\Parameters\EnableDynamicBacklog
    
    Type: REG_DWORD
    Value: 1
             HKLM\System\CurrentControlSet\Services
                 \AFD\Parameters\MinimumDynamicBacklog
    
    Type: REG_DWORD
    Value: 20
             HKLM\System\CurrentControlSet\Services
                 \AFD\Parameters\MaximumDynamicBacklog
    
    Type: REG_DWORD
    Value: 5000
             HKLM\System\CurrentControlSet\Services
                 \AFD\Parameters\DynamicBacklogGrowthDelta
    
    Type: REG_DWORD
    Value: 20
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\EnableDeadGWDetect
    
    Type: REG_DWORD
    Value: 0
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\KeepAliveTime
    
    Type: REG_DWORD
    Value: 300,000
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\PerformRouterDiscovery
    
    Type: REG_DWORD
    Value: 0
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\EnableICMPRedirects
    
    Type: REG_DWORD
    Value: 0
             HKLM\System\CurrentControlSet\Services
                 \Tcpip\Parameters\DisableIPSourceRouting
    
    Type: REG_DWORD
    Value: 2

Web server

The web server is a required component since it provides all user interface modules. It should therefore be carefully protected.

Since Password Manager does not require any web server functionality beyond the ability to serve static documents (HTML, images) and to execute self-contained CGI executable programs, all non-essential web server content should be removed.

Several web servers are commonly available for Windows servers, including Apache, IIS, iPlanet and more. Hitachi ID Systems suggests that the Apache or IIS web server be used with Password Manager. As such, this document will detail how to lock down the Apache or IIS web server.

Apache

The Apache server is recommended, as it is well supported and has had a very good security track record. Most recent web server security vulnerabilities have been specific to IIS, and would not affect Apache.

If you select Apache, you can harden it by:

  • Denying access from all clients except those coming from the internal domain. Do this by using the Allow, Deny directives for the Password Manager virtual directories.

  • Ensuring that you use only Apache modules that are needed by Password Manager. For example, you do not need modules for PERL, PHP or any other scripting languages. Read through the Apache configuration file and disable LoadModule directives by deleting or commenting them out in httpd.conf.

  • Moving the DocumentRoot to a different drive than your system disk (e.g., if your WINNT directory is on C:, then move DocumentRoot to D:).

IIS (Internet Information Server)

IIS is more than a web server - it is also an FTP server, indexing server, proxy for database applications and a server for active content / applications.

If you run Password Manager on IIS, you should disable most of these features, as each of them may represent a security risk, due to the possibility of software bugs.

Lock down IIS as follows:

Use separate NTFS partitions

Create two separate NTFS partitions - one for the operating system and one for IIS. This will separate most of the operating system files from the application files, allowing a more controlled distribution of permission sets.

Remove non-essential web server content

As stated previously, Password Manager only requires the web server to serve static documents (HTML, images) and to execute self-contained CGI executable programs, which means all non-essential web server content should be removed. This means removing IISAdmin, Printers, Scripts and similar folders, as shown in the figure below:

figure

The web server's scripting, indexing and data access subsystems should likewise be removed as shown in the figure below:

figure

Remove RDS registry keys

As an extra precaution, remote data services (RDS) should be disabled by removing the following registry keys:

               HKLM\System\CurrentControlSet\Services
                   \W3SVC\Parameters\ADCLaunch\RDSServer.DataFactory
    
               HKLM\System\CurrentControlSet\Services
                   \W3SVC\Parameters\ADCLaunch\AdvancedDataFactory
    
               HKLM\System\CurrentControlSet\Services
                   \W3SVC\Parameters\ADCLaunch\BusObj.VbBusObjCls
    

Remove ODBC drivers

All ODBC drivers that are not required (and Password Manager uses none) should also be disabled because they can introduce possible security concerns for IIS. To disable the ODBC drivers, remove the data sources manually and add this entry to the registry:

               HKLM\Software\Microsoft\Jet\4.0\engines\SandBoxMode = 3
    

The above registry entry will ensure that no cmd.exe commands can be chained with ODBC queries.

Consult the following Microsoft Knowledge Base article for more information:

http://support.microsoft.com/support/kb/articles/Q239/1/04.asp

Restrict IUSR and IWAM account permissions

The IUSR account is created during the IIS installation and provides the mechanism that allows web clients to access the web server anonymously. The IWAM account is used to start out-of-process web applications in IIS. Do not add these accounts to a privileged group such as Administrators. Delete these accounts if possible as Password Manager does not use them (it creates and uses the psadmin user for anonymous access).

Service packs

Install the latest service packs, as these frequently include security patches and updates.

Service packs for Windows 2003 may be found at:

http://technet.microsoft.com/en-us/windowsserver/bb512919

Service packs for Windows 2000 may be found at:

http://technet.microsoft.com/en-us/windowsserver

We recommend that to be notified of the latest security upgrades for Windows 2003, you subscribe to the Microsoft's security bulletin at:

http://www.microsoft.com/technet/security/bulletin/notify.asp

Equally important to installing the latest service pack is testing the service pack installation before deployment on a production platform. This will ensure there are no adverse affects on Password Manager.

Communication defenses

Password Manager sends and receives sensitive data over the network. Its communications include user passwords, administrator credentials and personal user information. These are all valuable assets that must be defended.

Network attacks typically fall into two classes:

  • Passive attacks, where an intruder listens to a communication stream and extracts useful data from it.
  • Active attacks, where an intruder abuses either an available network service, or an open communication session.

Hitachi ID Systems strongly recommends that users access Password Manager using SSL (HTTPS). To do this, you must:

  • Assign a fixed IP address to each Password Manager server.
  • Assign a fixed DNS name to each Password Manager server.
  • Install a web server.
  • Create a certificate signing request (CSR) file.
  • Submit the CSR file to a certificate authority (e.g. Verisign, Thawte, etc.).
  • Receive and install a signed certificate.

As long as the Password Manager server is configured with an SSL certificate, and configured to require HTTPS client communication, no sensitive data will be transmitted in plaintext. This will protect communications against both passive and active attacks.

Data protection

(1)

The Password Manager server houses some sensitive data, and this data must be protected against anyone who has physical access to the server, or has a legitimate right to log into it.

All sensitive data on the Password Manager server is encrypted, as follows:

Encryption is used to protect stored Password Manager data as follows:

Data stored on the Password Manager server
Data Algorithm Key
Privileged passwords, used to log into target systems 128-bit AES 128-bit random
Answers to security questions 128-bit AES 128-bit random
User old password history SHA-1 64-bit random salt

 

Of the above, the only mandatory data is administrator credentials for target systems. Everything else may be pulled by Password Manager from other systems (database, directory, etc.), on demand. Note, however, that moving sensitive data to another system generally introduces more security problems (communication, storage) than it solves, and is not recommended as a solution to security concerns.

As a result of this encryption, someone with access to the filesystem of the Password Manager server would not be able to readily decipher sensitive data on that server. They would first have to figure out where the data is stored, then how it is encoded, then how it is encrypted, and then they would have to find a suitable key (itself encrypted, in the Password Manager server's registry).

This provides as much protection as possible to sensitive data on the server, without compromising its functionality.

Auditing

Audit logs are an important measure to identify and analyze suspicious activity.

Since anyone with with administrator access to the Password Manager server can alter or remove audit logs, arrange for periodic archive of audit logs to a different server, managed by different administrators.

Windows 2003 provides various audit logs through the "Event Viewer." Additionally, IIS provides configurable logging information with W3C Extended Log File Format.

An audit log is only effective if it is examined. These logs provide the best indications of break-ins, fraud and misuse. Therefore, regular examination of the logs is recommended.

Physical security

Password Manager servers should be physically protected, since any logical security measures can be bypassed by an intruder with physical access to the server, time and skill.

Suggestions for physically securing the Password Manager server include:

  • Location and access

    Put the Password Manager server(s) in a locked and secured room. Restrict access to authorized personnel only. Access should be logged.

  • Power

    Protect the Password Manager server with uninterruptable power sources (UPS). UPS equipment will protect the server from temporary power loss that could cause a server crash or corruption of critical user files.

  • Removable media

    Restrict the boot process so it is more difficult for intruders to circumvent Windows 2003 security by booting from floppy disks or a CD-ROM. Specifically, use a BIOS-level password, disable boot from a floppy drive, flash device or CD-ROM drive and lock the system BIOS to prevent unauthorized changes to the BIOS configuration.

Conclusions

This document highlights the fact that Password Manager is a sensitive server, and should be managed carefully. In particular, it should be installed on a locked-down server, and managed with close attention to security.

This document illustrates the best-practice measures that should be implemented to protect Password Manager servers.

To learn more about hardening a Windows 2003 server, please refer to the Microsoft site:

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=8222

In case the above URL changes, search http://microsoft.com for the document titled "Windows Server 2003 Security Guide."

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