Spotting the Adversary with Windows Event Log Monitoring

More documents

Recommendations

Info

The maximum log file sizes are intended for the server whose role is the event collection server of the domain. Clients machine do not need to specify a maximum log size or retention policy. When Event Forwarding is properly configured, all events will be sent to the collector for archiving. 6 Final Recommendations The central collection of event information helps enterprises gain a better view of activities occurring on the network. Collecting targeted events has the benefit of reducing network and storage requirements while providing useful audit information. Targeted event collection reduces the burden and time required for administrators to review logs which may lead to administrators detecting unapproved or malicious activities. 7 Appendix 7.1 Subscriptions Event Forwarding on Windows uses subscriptions to specify which events from a set of computers to collect. The Operating System Based Subscriptions section discussed the issue of collecting events from an intermixed network and recommends a possible solution. This section discusses the details of subscriptions and custom subscriptions for Windows 7 and Windows XP computers. The sample subscription files in this section can be copied as XML files and loaded into the event collector using the command line tool, wecutil.exe. Each of the sample subscriptions do not specify whom is permitted to use the subscriptions (AllowedSourceDomainComputers is blank). The creation of the sample subscription can be completed by executing the following commands in order: 1. wecutil cs .xml a. An error stating The subscription fails to activate will appear so ignore it 2. wmic path Win32_group where name=’EventSources’ get sid a. Store this value temporarily If computers have been separated by their operating system version and placed into groups, execute wmic path Win32_group where name=’new_group_name’ get sid instead of step 2 above. The new_group_name needs to be either vplus or previs depending on targeted group. If a different group was created to represent the different Windows operating system versions, use that name in lieu of vplus or previs. 3. Obtain the value of the SubscriptionId element from the subscription XML file 4. Using the SID value found in step 2, correct the subscriptions configuration by executing wecutil ss SubscriptionId /adc:O:NSG:BAD:P(A;;GA;;;sid_value)S: 5. To verify that no issues are present, execute wecutil rs SubscriptionId The parameter /adc of wecutil is used to set a Security Descriptor Definition Language (SDDL) for the targeted subscription. SDDL is discussed in the Security Descriptor Definition Language section. 7.1.1 Subscription XML Details A subscription is simply a XML file that describes to the operating system what event logs to collect and forward. The following subscription example demonstrates the collection of all events in the Application log from a source (client). The targeted sources are the Domain Computers group and the Domain 37
Controllers group. This subscription example is for testing purposes as it will collect a large amount of events and is not recommended for production use. The example below conforms to the MS-WSMV: Web Services Management Protocol Extensions for Windows Vista, as the subscription was created on Windows Server 2008 R2. [56] Application Log SourceInitiated true http://schemas.microsoft.com/wbem/wsman/1/windows/EventLog MinLatency 30000 *[System[(Level=0 or Level= 1 or Level=2 or Level=3 or Level=4 or Level=5)]] ]]> false HTTP RenderedText ForwardedEvents Microsoft-Windows-EventCollector O:NSG:NSD:(A;;GA;;;DC)(A;;GA;;;DD) The following table details each node of the above subscription: [56] 56 wecutil ss -? 38
Page 1 and 2: National Security Agency/Central Se
Page 3 and 4: List of Figures Figure 1: Creating
Page 5 and 6: Disclaimer This Guide is provided "
Page 7 and 8: Initiated (pull) or Source-Initiate
Page 9 and 10: updates. A batch script is provided
Page 11 and 12: The compatibility listener binds Wi
Page 13 and 14: The Event Delivery Optimization opt
Page 15 and 16: The logging of cryptographic activi
Page 17 and 18: The WinRM service can be found by n
Page 19 and 20: Figure 10: Enable SubscriptionManag
Page 21 and 22: 3. Select Browse… and enter NETWO
Page 23 and 24: Figure 12: GPO Inbound Firewall Rul
Page 25 and 26: 3. In the Show Contents windows, en
Page 27 and 28: 1. Open Services MMC snap-in 2. Rig
Page 29 and 30: 3.1.1 Basic Authentication The clie
Page 31 and 32: Accessing each source to manually c
Page 33 and 34: To configure a WinRM service to run
Page 35 and 36: Windows 7 Windows Service Fails or
Page 37 and 38: ID Level Event Log Event Source Eve
Page 39 and 40: Detected an invalid image hash of a
Page 41: The XPath queries below are used fo
Page 45 and 46: The Enabled registry value should h
Page 47 and 48: Windows Kernel Driver Errors (Kerne
Page 49 and 50: User Account Added to Privileged Gr
Page 51 and 52: LogDel SourceInitiated Windows Fire
Page 53 and 54: XP_SysLogsErr SourceInitiated Windo
Page 55 and 56: Microsoft’s Events and Errors Mes
Page 57 and 58: WinRM Version (KB#) Supported OS KB
Page 59 and 60: Parameters MaxEnvelopeSizekb MaxTim
Page 61 and 62: EnableCompatibilityHttpsListener Se
Page 63 and 64: @ECHO OFF SETLOCAL SETLOCAL ENABLED
Page 65 and 66: O: Owner_SID G: Group_SID D: DACL_F
Page 67 and 68: Generally, WinRM produces an error
Page 69 and 70: Failed to open subscription. Error
Page 71 and 72: When a WinRM connection arrives on

Spotting the Adversary with Windows Event Log Monitoring

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?