Understanding the Event Log for a more secured environment

Dave MillierChuck Ben-Tzur

Understanding the Event Log for a more secured environment

Overview

Introducing… the Event LogWhy Monitor LogsEnabling Event LoggingReal Time Monitoring

Example: Security Log TamperingAuditing and AnalysisArchiving Events

Example: File Modification InvestigationEvent Log LimitationVista Event Log

Example: Creating Log File Using Event Triggered TasksResources and Questions

Introducing…Event Log

Centralized log service to allow applications and the operating system to report events that have taken place.Introduced with Windows NT 4 (1993).Main Windows Logs

Application (example: Database message)System (example: driver failure)Security (example: Logon attempt, file access)

A Windows 2003 domain controller will also include

Directory Service (example: Active Directory connection problem)File Replication (example: domain controller information updates)DNS

Vista has introduced a lot of changes

Why Should We Monitor Logs

We don’t NEED to… We HAVE to…Organizations are obligated by regulations to gather and audit systems activity logs.

HIPPA (Health Industry)Regulatory review of system activity to ensure that a user information remains private but accessibleIdentify, respond and document security incidents

GLBA (Financial)Dual control proceduresSegregation of duties

SOX (Financial)Record Retention and availabilityAccountability

Why Should We Monitor Logs (cont.)

To comply with the regulations organizations require the following forms of log monitoring

Real-time monitoringIdentify attack attempts in progress and if a security breach has occurred.

Audit and analysisPeriodic reports and analysis for regulation compliance (due diligence).

ArchivingAgain… regulations compliance (log retention)Forensic investigation of an incident

The event log should also enable the organization to implement internal security policies.

Enabling Event Logging

Each event category is controlled by audit policies:Account logon events (for domain accounts)Account management (group and account events)Directory service accessLogon events (local machine events)Object access (user accessing an object such as file, folder, printer)Policy change (changes in the audit, user rights and trust policies)Privilege use (user exercising one or more of his rights)Process tracking (detailed tracking information)System events (events that affect the system security or log)

Each policy can be set to audit success events only, failure events only, success/failure events, or no auditing at all.

Audit Policies (Member Server)

Real-Time Monitoring

Successful events that grant the user high level privileges (either by spoofing identity or elevation of privileges)Events to monitor

Successful high profile user account / group management events#636– Group member added or removed

Successful logon events of high profile user accounts#680 – Logon attempt

Successful logon events to a domain controllerOperations on specific high profile resources (files, folder)

#560 (Object Access), #564 (Object Deleted)Successful policy change events

#612 – Audit Policy Change (logs no more…)All system events

#517 – security log was cleared

Example: Event #517 (Clear Security Log)

Security Log


Security LogA User will try to erase the logs


Security LogA User will try to erase the logs (and not event save it)


Security LogA User will try to erase the logsA New Event is Created


Security LogA User will try to erase the logsA New Event is CreatedThe Event Contains the User Name

Real-Time Monitoring (cont.)

Tracking and analysing event failure patterns may indicate a range of malicious attack attempts

Failed logon activity (e.g. brute force attack)#675 – Pre Auth, failed with Kerberos code 24 (Bad password)#539 - logon failure due to account lockout (if systematic may be an indication of DoS)

Failed account management activity (e.g. password reset events)All failed system events

#517 – Audit log clearedNote: Most of the auditing policies, by default, are set to log

successful events only. Local policies may be set to no auditing at all.

Real-Time Monitoring (cont.)

Possible issuesFlood of events (domain controller and member server event duplication, detailed tracking events)

Solution: Consolidate log information for better analysisUnmonitored systems (e.g. unaudited events on a file server)

Solution: Threat modeling, identifying assets in organizationUnmonitored events (detailed user and process activity)

Solution: Organization security program and policiesFalse positives due to configuration problems (e.g. expired service password)

Solution: Knowledge of the network, components and assets (Human Factor)

Auditing and Analysis

Most regulations require a periodic review of important events (not critical or show stoppers) for two reasons:

A “second chance” to reveal malicious activity originally undetected (and unaccountable for).Audit the ongoing activity to verify no major changes have taken place.

The data is usually reviewed in the form of reports

(detailed and summarized)Example of Events to Monitor (A short list)

#529 to #535 and #539 – Logon failure (different reasons)#629 – User account Disabled#644 – User account Locked Out

Auditing and Analysis (cont.)

Possible issuesFinding a critical event that was not detected by the real-time monitoring processes

Solution: Investigate the incident to eliminate or mitigate any results of malicious activity.

Duplicated events (Domain controller and Local Server)Solution: Correlate and consolidate events using external system

Lack of security policies to help and identify events to be audited (e.g. Messenger)

Solution: Define security policies to determine which event types need to be audited on a regular basis.

Report requirements are unclear and affect the log detail levelSolution: Define auditing processes to determine what type of logs and details are required (TIP: when in doubt, use graphs…)

Archiving Events

Event Archiving is done for two main reasons:Log retention compliance (e.g. SOX)Forensic investigation of a security incident (chain of evidence)

In general, all system events should be logged. However, by default, not all audit policies are set to generate logs.In particular, detailed tracking of high profile objects (such as files, folders, printers, etc.) is turned off by default. A common misconception is that regular object access events provide this information.

Example: Detailed Event Tracking

Detailed Event tracking can include the following events:

#528 – Successful Login (The user authenticate to the system)#592 – A new process has been created (application is launched)#560 – Object Open (a file is requested)#567 – Object Access (the file is modified and saved)#564 – Object Deleted#562 – Handle Closed (the file has been closed)#593 – A Process Has Exited (the application was terminated)


Enabling Audit Policies

Object AccessLogon (Local and Domain)Privilege UseProcess Tracking


A Very Important Folder (e.g. sensitive document on a file server)


A Very Important Folder (e.g. sensitive document on a file server)The folder contains files we wish to monitor (compliance, sensitive information, etc.)


Detailed Tracking is configured on the resource itself


Detailed Tracking is configured on the resource itselfSecurity > Advanced


Detailed Tracking is configured on the resource itselfSecurity > Advanced > Auditing Tab


Detailed Tracking is configured on the resource itselfSecurity > Advanced > Auditing Tab > Add


Detailed Tracking is configured on the resource itselfSecurity > Advanced > Auditing Tab > AddSelect the Account or Group to be audited


Detailed Tracking is configured on the resource itselfSecurity > Advanced > Auditing Tab > AddSelect the Account or Group to be auditedSelect the events to audit (Read, Write, Delete…)


Detailed Tracking is configured on the resource itselfSecurity > Advanced > Auditing Tab > AddSelect the Account or Group to be auditedSelect the events to audit (Read, Write, Delete…)Each user/group will require additional settings


Timestamp: 13-06-07 04:27:40


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39

Filter who was logged in during

that time


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744D


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916File Open Handle: 644


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916File Open Handle: 644File (644) Modified at 05:27:39


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916File Open Handle: 644File (644) Modified at 05:27:39File (644) closed


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916File Open Handle: 644File (644) Modified at 05:27:39File (644) closedExcel Process (2916) Terminated


Timestamp: 13-06-07 04:27:40Last Modify: 13-06-07 05:27:39User Logon ID: 0x43F744DExcel Process ID: 2916File Open Handle: 644File (644) Modified at 05:27:39File (644) closedExcel Process (2916) TerminatedMatching Modification Times

Archiving Events (cont.)

Possible issuesVolume of events (can reach several million events a day from a busy server)

Solution: Transfer logs to long-term storage (compressed, digitally signed, etc.)

Lack of security policies to help and identify events and processes to be audited (e.g. Messenger)

Solution: Define security policies to determine which processes and their relevant events need to be logged on a regular basis.

The event logs are just a portion of the “chain of evidence”

Solution: Define auditing processes to ensure that all the required logs are being gathered and associated (e.g. a unique ID or a time stamp). For example: associate firewall logs through the Windows event logs and to the database logs.

Know Your Event Log Limits

Size matters (and its never enough…)Solution: For long term logging, use an external storage system.

Know Your Event Log Limits (cont.)

Log Analysis and correlation (especially when using automatic systems like SEM and SIM) often result in a large number of false positives.

Solution: Knowledge of the network and assets to refine alerts, ongoing tuning

Logs are a “detective” measure and are not an IPS (Intrusion prevention system) on their own

Solution: Vista has a partial solution. For complicated responses, leverage external solution to gather and analyze logs

Not all events are logged on the domain controller. These events require a log gathering process

Solution: Vista has presented a solution. Otherwise, use external log gathering system.

Know Your Event Log Limits (cont.)

Security event logs monitor only the authentication and authorization mechanisms of the operating system.

Solution: Most applications write (or should…) logs to the Windows event log. These logs can be used to enhance the monitoring capabilities.

Custom application logs neglect to provide information regarding the log details or the severity or of the event.

Solution: Educate your developers, develop an API, buy something better…

Vista Event Log

More Categori

es

More Event

Sources

Vista Event Log

Redesigned

Vista Event Log

RedesignedXML Based

Vista Event Log

RedesignedXML BasedSimple to Understand

Vista Event Log

RedesignedXML BasedSimple to Understand.

Vista Event Log

RedesignedXML BasedSimple to Understand..??

Vista Event Log

RedesignedXML BasedSimple to Understand….

Event Log Tasks (Vista)

Select an Event


Select an Event to open the Wizard


Select an Event to open the WizardThe type of Event is pre-selected (basic)


Select an Event to open the WizardThe type of Event is pre-selected (basic)Select Action



e-mail settings



Launch a process


Select an Event to open the WizardThe type of Event is pre-selected (basic)Select ActionFinalize Settings


Select an Event to open the WizardThe type of Event is pre-selected (basic)Select ActionFinalize SettingsA New Task is Born…


Select an Event to open the WizardThe type of Event is pre-selected (basic)Select ActionFinalize SettingsTask CreatedTask is Visible in the Task Scheduler


Select an Event to open the WizardThe type of Event is pre-selected (basic)Select ActionFinalize SettingsTask CreatedTask is Visible in the Task Scheduler (new Tasks Category)


Problem: Basic Task Event Details are pre-defined.


Problem: Basic Task Event Details are pre-defined.

The next example will:

• Trigger on successful logon events of a specific

group

• Create a file with a list of users that logged on

• Highlight username with “Admin” string


Create a New Task


Create a New TaskSelect the User Group


Create a New TaskSelect the User GroupTriggers Tab > New


Create a New TaskSelect the User GroupTrigger Task On an Event


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…Select Event Logs


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…Select Event Logs (Multiple Logs!)


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…Select Event Logs (Multiple Logs!)Select Events ID (Possible Multiple IDs) and Keywords


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…Select Event Logs (Multiple Logs!)Select Events ID (Possible Multiple IDs)The trigger is saved as XMLQuery (Can be modified)


Create a New TaskSelect the User GroupTrigger Task On an EventSwitch from Basic to Custom and Create New Filter…Select Event Logs (Multiple Logs!)Select Events ID (Possible Multiple IDs)The trigger is saved as XMLQuery (Can be modified)The Task Action will be “Select a Program”…


This VB script search for “Admin” string in the logged user name and add a notes beside it.


The output of three different users logging to the machine…

Event Log @ Vista

New Event Viewer (interface)Over 50 new Event categoriesOver 2400 policies (over 1000 in W2K3)XML basedEvents are still written locallyCritical Events can be forwarded Expanded to serve as single location for all events (using Windows Remote Manager)Events can launch system tasks

Resources

TechNet – Auditing Overview (http://technet2.microsoft.com/windowsserver/en/library/768463f6-02b9-4e5e-af55-29c089ade6381033.mspx?mfr=true)

EventID.net (http://www.eventid.net/search.asp)

Randy Franklin Smith’s Windows Security Log Encyclopedia (http://www.ultimatewindowssecurity.com/encyclopedia.html)

http://technet2.microsoft.com/windowsserver/en/library/768463f6-02b9-4e5e-af55-29c089ade6381033.mspx?mfr=true

http://technet2.microsoft.com/windowsserver/en/library/768463f6-02b9-4e5e-af55-29c089ade6381033.mspx?mfr=true

http://www.eventid.net/search.asp

http://www.ultimatewindowssecurity.com/encyclopedia.html

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Questions…?

Understanding the Event Log for a more secured environment

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