THIS IS A EXPERIMENTAL DETECTION
This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.
This search will return a table of rare processes, the names of the systems running them, and the users who initiated each process.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2020-03-16
- Author: Bhavin Patel, Splunk
- ID: 44fddcb2-8d3b-454c-874e-7c6de5a4f7ac
Kill Chain Phase
- Command & Control
- Actions on Objectives
- CIS 2
- CIS 8
1 2 3 4 5 6 7 8 9 10 11 12 13 | tstats `security_content_summariesonly` count values(Processes.dest) as dest values(Processes.user) as user min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes by Processes.process_name | rename Processes.process_name as process | rex field=user "(?<user_domain>.*)\\\\(?<user_name>.*)" | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | search [ | tstats count from datamodel=Endpoint.Processes by Processes.process_name | rare Processes.process_name limit=30 | rename Processes.process_name as process | `filter_rare_process_allow_list` | table process ] | `detect_rare_executables_filter`
The SPL above uses the following Macros:
detect_rare_executables_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 must be ingesting data that records process activity from your hosts and populating the endpoint data model with the resultant dataset. The macro
filter_rare_process_allow_list searches two lookup files for allowed processes. These consist of
rare_process_allow_list_local.csv. To add your own processes to the allow list, add them to
rare_process_allow_list_local.csv. If you wish to remove an entry from the default lookup file, you will have to modify the macro itself to set the allow_list value for that process to false. You can modify the limit parameter and search scheduling to better suit your environment.
Known False Positives
Some legitimate processes may be only rarely executed in your environment. As these are identified, update
rare_process_allow_list_local.csv to filter them out of your search results.
Associated Analytic Story
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 5