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Understanding the Event Log for a more secured environment

Understanding the Event Log for a more secured environment. Dave Millier Chuck Ben-Tzur. Overview. Introducing… the Event Log Why Monitor Logs Enabling Event Logging Real Time Monitoring Example: Security Log Tampering Auditing and Analysis Archiving Events

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Understanding the Event Log for a more secured environment

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  1. Understanding the Event Log for a more secured environment Dave Millier Chuck Ben-Tzur

  2. Overview • Introducing… the Event Log • Why Monitor Logs • Enabling Event Logging • Real Time Monitoring • Example: Security Log Tampering • Auditing and Analysis • Archiving Events • Example: File Modification Investigation • Event Log Limitation • Vista Event Log • Example: Creating Log File Using Event Triggered Tasks • Resources and Questions

  3. 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

  4. 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 accessible • Identify, respond and document security incidents • GLBA (Financial) • Dual control procedures • Segregation of duties • SOX (Financial) • Record Retention and availability • Accountability

  5. Why Should We Monitor Logs (cont.) • To comply with the regulations organizations require the following forms of log monitoring • Real-time monitoring • Identify attack attempts in progress and if a security breach has occurred. • Audit and analysis • Periodic reports and analysis for regulation compliance (due diligence). • Archiving • Again… regulations compliance (log retention) • Forensic investigation of an incident • The event log should also enable the organization to implement internal security policies.

  6. 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 access • Logon 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.

  7. Audit Policies (Member Server)

  8. 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 controller • Operations 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

  9. Example: Event #517 (Clear Security Log) Security Log

  10. Example: Event #517 (Clear Security Log) Security Log A User will try to erase the logs

  11. Example: Event #517 (Clear Security Log) Security Log A User will try to erase the logs (and not event save it)

  12. Example: Event #517 (Clear Security Log) Security Log A User will try to erase the logs A New Event is Created

  13. Example: Event #517 (Clear Security Log) Security Log A User will try to erase the logs A New Event is Created The Event Contains the User Name

  14. 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 cleared Note: Most of the auditing policies, by default, are set to log successfulevents only. Local policies may be set to noauditing at all.

  15. Real-Time Monitoring (cont.) • Possible issues • Flood of events (domain controller and member server event duplication, detailed tracking events) • Solution: Consolidate log information for better analysis • Unmonitored systems (e.g. unaudited events on a file server) • Solution: Threat modeling, identifying assets in organization • Unmonitored events (detailed user and process activity) • Solution: Organization security program and policies • False positives due to configuration problems (e.g. expired service password) • Solution: Knowledge of the network, components and assets (Human Factor)

  16. 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

  17. Auditing and Analysis (cont.) • Possible issues • Finding 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 level • Solution: Define auditing processes to determine what type of logs and details are required (TIP: when in doubt, use graphs…)

  18. 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.

  19. 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)

  20. Example: Detailed Event Tracking • Enabling Audit Policies • Object Access • Logon (Local and Domain) • Privilege Use • Process Tracking

  21. Example: Detailed Event Tracking A Very Important Folder (e.g. sensitive document on a file server)

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

  23. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself

  24. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced

  25. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab

  26. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab > Add

  27. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab > Add

  28. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab > Add Select the Account or Group to be audited

  29. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab > Add Select the Account or Group to be audited Select the events to audit (Read, Write, Delete…)

  30. Example: Detailed Event Tracking Detailed Tracking is configured on the resource itself Security > Advanced > Auditing Tab > Add Select the Account or Group to be audited Select the events to audit (Read, Write, Delete…) Each user/group will require additional settings

  31. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40

  32. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39

  33. Example: Detailed Event Tracking Filter who was logged in during that time Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39

  34. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D

  35. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916

  36. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644

  37. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644

  38. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644 File (644) Modified at 05:27:39

  39. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644 File (644) Modified at 05:27:39 File (644) closed

  40. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644 File (644) Modified at 05:27:39 File (644) closed Excel Process (2916) Terminated

  41. Example: Detailed Event Tracking Timestamp: 13-06-07 04:27:40 Last Modify: 13-06-07 05:27:39 User Logon ID: 0x43F744D Excel Process ID: 2916 File Open Handle: 644 File (644) Modified at 05:27:39 File (644) closed Excel Process (2916) Terminated Matching Modification Times

  42. Archiving Events (cont.) • Possible issues • Volume 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.

  43. Know Your Event Log Limits • Size matters (and its never enough…) • Solution: For long term logging, use an external storage system.

  44. 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.

  45. 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…

  46. Vista Event Log More Categories More Event Sources

  47. Vista Event Log • Redesigned

  48. Vista Event Log • Redesigned • XML Based

  49. Vista Event Log • Redesigned • XML Based • Simple to Understand

  50. Vista Event Log • Redesigned • XML Based • Simple to Understand.

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