Блокировка сбора признаков активности
An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting (Citation: Microsoft Lamin Sept 2017) or even disabling host-based sensors, such as Event Tracing for Windows (ETW),(Citation: Microsoft About Event Tracing 2018) by tampering settings that control the collection and flow of event telemetry. (Citation: Medium Event Tracing Tampering 2018) These settings may be stored on the system in configuration files and/or in the Registry as well as being accessible via administrative utilities such as PowerShell or Windows Management Instrumentation. ETW interruption can be achieved multiple ways, however most directly by defining conditions using the PowerShell Set-EtwTraceProvider cmdlet or by interfacing directly with the registry to make alterations. In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process responsible for forwarding telemetry and/or creating a host-based firewall rule to block traffic to specific hosts responsible for aggregating events, such as security information and event management (SIEM) products.
Контрмеры |
|
| Контрмера | Описание |
|---|---|
| User Account Management |
Manage the creation, modification, use, and permissions associated to user accounts. |
| Indicator Blocking Mitigation |
Ensure event tracers/forwarders (Citation: Microsoft ETW May 2018), firewall policies, and other associated mechanisms are secured with appropriate permissions and access controls. Consider automatically relaunching forwarding mechanisms at recurring intervals (ex: temporal, on-logon, etc.) as well as applying appropriate change management to firewall rules and other related system configurations. |
| Restrict File and Directory Permissions |
Restrict access by setting directory and file permissions that are not specific to users or privileged accounts. |
| Software Configuration |
Implement configuration changes to software (other than the operating system) to mitigate security risks associated to how the software operates. |
Обнаружение
Detect lack of reported activity from a host sensor. Different methods of blocking may cause different disruptions in reporting. Systems may suddenly stop reporting all data or only certain kinds of data.
Depending on the types of host information collected, an analyst may be able to detect the event that triggered a process to stop or connection to be blocked. For example, Sysmon will log when its configuration state has changed (Event ID 16) and Windows Management Instrumentation (WMI) may be used to subscribe ETW providers that log any provider removal from a specific trace session. (Citation: Medium Event Tracing Tampering 2018) To detect changes in ETW you can also monitor the registry key which contains configurations for all ETW event providers: HKLM\SYSTEM\CurrentControlSet\Control\WMI\Autologger\AUTOLOGGER_NAME\{PROVIDER_GUID}
Ссылки
- Palantir. (2018, December 24). Tampering with Windows Event Tracing: Background, Offense, and Defense. Retrieved June 7, 2019.
- Microsoft. (2018, May 30). About Event Tracing. Retrieved June 7, 2019.
- Microsoft. (2009, May 17). Backdoor:Win32/Lamin.A. Retrieved September 6, 2018.
- Microsoft. (2018, May 30). Event Tracing. Retrieved September 6, 2018.
Связанные риски
Каталоги
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