The following analytic identifies native .net binaries within the Windows operating system that may be abused by adversaries by moving it to a new directory. The analytic identifies the .net binary by using a lookup and compares the process name and original file name (internal name). The analytic utilizes a lookup with the is_net_windows_file macro to identify the binary process name and original file name. if one or the other matches an alert will be generated. Adversaries abuse these binaries as they are native to windows and native DotNet. Note that not all SDK (post install of Windows) are captured in the lookup.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-01-19
- Author: Michael Haag, Splunk
- ID: fddf3b56-7933-11ec-98a6-acde48001122
Kill Chain Phase
1 2 3 4 5 6 7 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where NOT (Processes.process_path IN ("*\\Windows\\ADWS\\*","*\\Windows\\SysWOW64*", "*\\Windows\\system32*", "*\\Windows\\NetworkController\\*", "*\\Windows\\SystemApps\\*", "*\\WinSxS\\*", "*\\Windows\\Microsoft.NET\\*")) by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.original_file_name Processes.process_path Processes.process_id Processes.parent_process_id | `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `is_net_windows_file` | `windows_dotnet_binary_in_non_standard_path_filter`
The SPL above uses the following Macros:
windows_dotnet_binary_in_non_standard_path_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
False positives may be present and filtering may be required. Certain utilities will run from non-standard paths based on the third-party application in use.
Associated Analytic Story
- Masquerading - Rename System Utilities
- Unusual Processes
- Signed Binary Proxy Execution InstallUtil
|49.0||70||70||An instance of $parent_process_name$ spawning $process_name$ from a non-standard path was identified on endpoint $dest$ by user $user$.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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