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ITL Bulletin for October 2006




ITL Bulletin for October 2006
ITL Bulletin for October 2006



Forwarded from: Elizabeth Lennon 

ITL BULLETIN FOR OCTOBER 2006

LOG MANAGEMENT: USING COMPUTER AND NETWORK RECORDS TO 
IMPROVE INFORMATION SECURITY

Shirley Radack, Editor
Computer Security Division
Information Technology Laboratory
National Institute of Standards and Technology
Technology Administration
U.S. Department of Commerce

The information that is routinely collected about specific events 
occurring within information technology (IT) systems and networks can be 
used by organizations to improve the security of their operations. This 
information is recorded as an entry in a log, and each log entry can be 
linked to a particular event. Log entries, which can be analyzed when 
organizations need to identify security incidents and operational 
problems, provide valuable information to managers who are responsible 
for the operations and security of systems.

Log entries are recorded by the systems' software and applications. The 
entries containing information related to system security are produced 
by several sources. Some log entries are created by security software, 
such as antivirus software, firewalls, intrusion detection systems, and 
intrusion prevention systems. Other sources of security-related log 
entries are the operating systems on an organization's servers, 
workstations, and networking equipment, and the applications on the 
systems.

Guide to Computer Security Log Management

NIST's Information Technology Laboratory recently issued Special 
Publication (SP) 800-92, Guide to Computer Security Log Management, by 
Karen Kent and Murugiah Souppaya, to help organizations develop, 
implement, and maintain effective processes for managing logs with 
security-related information. The guide explains how sound log 
management practices can support the overall security of an 
organization's systems and information.

NIST SP 800-92 begins with basic information about computer security 
logs, the usefulness of these logs, and the challenges of managing them. 
Topics covered in depth in the guide include the components of the log 
management infrastructure, including the hardware, software, networks, 
and media that are used to generate, transmit, store, analyze, and 
dispose of log information; the planning processes that enable the 
organization to carry out consistent, reliable, and efficient log 
management practices; and the operational processes that aid 
organizations in successfully managing logs.

In the appendices to the guide, you will find a glossary of terms used, 
a list of acronyms, and an extensive listing of tools and resources that 
should be helpful in understanding and implementing log management in 
your organization. Both in-print and online resources are included. NIST 
SP 800-92 is available from NIST's web pages at:

http://csrc.nist.gov/publications/nistpubs/index.html. 

Logs and Their Uses

Logs are records of many different, specific events that occur within an 
organization's systems and networks. In the past, the information 
recorded in logs was used primarily to identify operational problems. 
Today, the information provided by logs is used for many purposes:

* optimizing system and network performance; to record the actions of 
  users;

* identifying security incidents, policy violations, fraudulent 
  activities, and operational problems;

* performing audits and forensic analyses;

* supporting internal investigations;

* establishing baselines; and

* identifying operational trends and long-term problems.

NIST's guide focuses on helping organizations manage the use of logs to 
improve IT security. While many logs are created by IT systems and could 
provide data that is useful for security, NIST SP 800-92 focuses on the 
logs that are closely related to computer security. For example, audit 
logs track user authentication attempts, and security device logs record 
possible attacks on systems. In managing computer security-related log 
data, organizations have to create, transmit, store, analyze and dispose 
of the data correctly.  The computer security records should be stored 
in sufficient detail for an appropriate period of time and be available 
for routine log analysis. Federal organizations have to take into 
account the requirements of laws, regulations, and organizational 
policies. For example, federal organizations may need to analyze the log 
information for compliance with federal legislation and regulations, 
including:

* Federal Information Security Management Act of 2002 (FISMA) - requires 
  federal agencies to develop, document, and implement an 
  organization-wide program to provide information security for the 
  information systems that support its operations and assets.

* Health Insurance Portability and Accountability Act of 1996 (HIPAA)
  - mandates safeguarding the confidentiality, integrity, and 
  availability of electronically protected health information.

* Sarbanes-Oxley Act of 2002 (SOX) - applies to financial and accounting 
  practices and the IT functions that support these practices.

* Gramm-Leach-Bliley Act (GLBA) - requires financial institutions to 
  protect their customers' information against security threats.

Managing Computer Security Logs

One of the challenges to the effective management of computer security 
logs is balancing the availability of large amounts of log information 
with the limited availability of organizational resources for analysis 
of the data. A large amount of information is collected daily by a large 
number of logs, and there are increasing threats to networks and 
systems. Organizations could realize benefits in using the data to 
reduce risks, but the staff time and resources needed to perform the 
analyses and to manage the log information have to be taken into 
consideration.

The large number of log information sources may produce inconsistent and 
incompatible content, formats, and time stamp information, making it 
difficult for analysts to understand the meaning of the data collected. 
Organizations may have to utilize automated methods to convert logs with 
different content and formats to a single standard format with 
consistent data field representations.

Another challenge is protecting the confidentiality, integrity, and 
availability of log information. Information such as users' passwords 
and the content of e-mails may be captured by logs. This raises security 
and privacy concerns involving both the individuals that review the logs 
and others that might be able to access the logs through either 
authorized or unauthorized means. Logs that are secured improperly in 
storage or in transit might also be susceptible to alteration and 
destruction by both intentional and unintentional techniques. As a 
result, malicious activities might go unnoticed and evidence could be 
manipulated to conceal the identity of a malicious party.

Log information should be analyzed on a regular basis and in a timely 
fashion by security, system, and network administrators. These staff 
members need support for their exacting tasks. They especially need 
training on how to carry out the log analysis procedures and how to 
prioritize their activities effectively. They should also be provided 
with tools that can automate portions of the analysis process, such as 
scripts and security software tools. These tools can be helpful in 
finding patterns that humans cannot easily perceive, such as correlating 
entries from multiple logs that are related to the same event.  
Analysis of logs by staff members has to be an ongoing activity so that 
organizations can predict future problems and prevent them.  In the 
past, many logs have not been analyzed in a timely manner. When 
organizations do not institute sound processes for analyzing logs, the 
value of the logs is significantly reduced.

Organizations also need to protect the availability of their logs. Many 
logs have a maximum size; for example, the software is limited to 
storing the 10,000 most recent events, or keeping 100 megabytes of log 
data. When the size limit is reached, the log might overwrite old data 
with new data or completely stop collecting log information.  Both of 
these outcomes result in the loss of availability of log data. To meet 
data retention requirements, organizations might need to keep copies of 
log files for a longer period of time than the original log sources can 
support. It may be necessary to establish processes to archive the log 
information.

Because of the volume of logs and the costs of archiving log data, it 
can be appropriate in some cases to reduce the logs by filtering out log 
entries that do not need to be archived.  The confidentiality and 
integrity of the archived logs also need to be protected.

NIST Recommendations for Log Management

NIST recommends that organizations carry out the following actions for 
more effective and efficient log management processes:

* Establish policies and procedures for log management.  Organizations 
  should develop standard processes for performing log management. In 
  the planning process, logging requirements and goals should be 
  defined. Based on those goals and requirements, an organization can 
  then develop policies that clearly define mandatory requirements and 
  suggested recommendations for log management activities, including log 
  generation, transmission, storage, analysis, and disposal. An 
  organization should also ensure that related policies and procedures 
  incorporate and support the log management requirements and 
  recommendations. The organization's management should provide the 
  necessary support for the efforts involving log management planning, 
  policy, and procedures development.

Policies and procedures help to assure a consistent approach and 
implementation of laws and regulatory requirements throughout the 
organization. Audits, testing, and validation procedures can help to 
assure that the logging standards and guidelines are being followed.

Requirements and recommendations for logging should be created in 
conjunction with an analysis of the technology and resources needed to 
implement the log management process. Generally, organizations should 
require logging and analyzing the data that is of the greatest 
importance, and should also have non-mandatory recommendations for the 
other types and sources of data that should be logged and analyzed if 
time and resources permit. In some cases, organizations can choose to 
have all or nearly all of its log data generated and stored for at least 
a short period of time in case it is needed. This policy gives greater 
weight to security considerations than to usability and resource usage. 
Also this policy can support better decision making in some cases. When 
establishing requirements and recommendations, organizations should 
strive to be flexible since each system is different and will log 
different amounts of data than other systems within the organization.

The organization's policies and procedures should also address the 
preservation of original logs. Many organizations send copies of network 
traffic logs to centralized devices. In addition, they may use tools 
that analyze and interpret network traffic. In cases where logs may be 
needed as evidence in proceedings, organizations may wish to acquire 
copies of the original log files, the centralized log files, and 
interpreted log data.  This policy is useful in case there are any 
questions regarding the fidelity of the copying and interpretation 
processes.  Retaining logs for evidence may involve the use of different 
forms of storage and different processes, such as putting additional 
restrictions on access to the records.

* Prioritize log management appropriately throughout the organization. 
  After an organization defines its requirements and goals for the log 
  management process, it should then prioritize its requirements and 
  goals based on the organization's perceived reduction of risk and the 
  expected time and resources needed to perform log management 
  functions.  An organization should also define roles and 
  responsibilities for log management for key personnel throughout the 
  organization, including establishing log management duties at both the 
  individual system level and the log management infrastructure level.

* Create and maintain a log management infrastructure. A log management 
  infrastructure consists of the hardware, software, networks, and media 
  used to generate, transmit, store, analyze, and dispose of log data. 
  Log management infrastructures normally perform several functions that 
  support the analysis and security of log data.  After establishing an 
  initial log management policy and identifying roles and 
  responsibilities, an organization should develop one or more log 
  management infrastructures that can effectively support the policy and 
  roles.  Organizations should consider implementing log management 
  infrastructures that includes centralized log servers and log data 
  storage. When designing infrastructures, organizations should plan for 
  both the current and future needs of the infrastructures and the 
  individual log sources throughout the organization. Major factors that 
  should be considered in the design include the volume of log data to 
  be processed, network bandwidth, online and offline data storage, the 
  security requirements for the data, and the time and resources needed 
  for staff to analyze the logs.

* Provide proper support for all staff with log management 
  responsibilities. To ensure that log management for individual systems 
  is performed effectively throughout the organization, the 
  administrators of those systems should receive adequate support.  
  This should include disseminating information to log management staff, 
  providing training, designating points of contact to answer questions, 
  providing specific technical guidance, and making tools and 
  documentation available.

* Establish standard log management operational processes.  The major 
  log management operational processes include configuring log sources, 
  performing log analysis, initiating responses to identified events, 
  and managing long-term storage. In addition, administrators have other 
  responsibilities, such as:

* Monitoring the logging status of all log sources;

* Monitoring log rotation and archival processes;

* Checking for upgrades and patches to logging software, and acquiring, 
  testing, and deploying them;

* Ensuring that each logging host's clock is synchronized to a common 
  time source;

* Reconfiguring logging as needed, based on policy changes, technology 
  changes, and other factors; and

* Documenting and reporting anomalies in log settings, configurations, 
  and processes.

More Information

Other NIST publications that support log management processes include:

NIST SP 800-31, Intrusion Detection Systems (IDS), provides information 
about hardware and software systems that automate the processes of 
monitoring events occurring in computer systems and networks, and of 
analyzing them for signs of security problems.

NIST SP 800-40 version 2, Creating a Patch and Vulnerability Management 
Program, provides guidance on creating a security patch and 
vulnerability management program, and on testing the effectiveness of 
the program.

NIST SP 800-41, Guidelines on Firewalls and Firewall Policy, provides 
guidance on the development of policies to guide the selection, 
installation and maintenance of firewalls that protect systems connected 
to the Internet and to other networks.

NIST SP 800-83, Guide to Malware Incident Prevention and Handling, 
discusses how to protect the confidentiality, integrity, and 
availability of data, applications, and operating systems by preventing 
and handling incidents involving the insertion of malicious code and 
software into systems.

These and other NIST publications can help you in planning and 
implementing a comprehensive approach to IT security.  Information about 
the NIST publications that are referenced in this bulletin, as well as 
other security-related publications, is available at

http://csrc.nist.gov/publications/index.html. 

Disclaimer
Any mention of commercial products or reference to commercial 
organizations is for information only; it does not imply recommendation 
or endorsement by NIST nor does it imply that the products mentioned are 
necessarily the best available for the purpose.


Elizabeth B. Lennon
Writer/Editor
Information Technology Laboratory
National Institute of Standards and Technology
100 Bureau Drive, Stop 8900
Gaithersburg, MD 20899-8900
Telephone (301) 975-2832
Fax (301) 975-2378


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