Windows File Without Extension In Critical Folder
This analytic is to look for suspicious file creation in the critical folder like "System32\Drivers" folder without file extension. This artifacts was seen in latest hermeticwiper where it drops its driver component in Driver Directory both the compressed(without file extension) and the actual driver component (with .sys file extension). This TTP is really a good indication that a host might be compromised by this destructive malware that wipes the boot sector of the system.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-02-25
- Author: Teoderick Contreras, Bhavin Patel, Splunk
- ID: 0dbcac64-963c-11ec-bf04-acde48001122
Kill Chain Phase
- CIS 3
- CIS 5
- CIS 16
1 2 3 4 5 6 7 8 9 10 11 12 | tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Filesystem where Filesystem.file_path IN ("*\\System32\\drivers\\*", "*\\syswow64\\drivers\\*") by _time span=5m Filesystem.dest Filesystem.user Filesystem.file_name Filesystem.file_path Filesystem.process_guid Filesystem.file_create_time | `drop_dm_object_name(Filesystem)` | rex field="file_name" "\.(?<extension>[^\.]*$)" | where isnull(extension) | join process_guid [ | tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by _time span=5m Processes.process_name Processes.dest Processes.process_guid Processes.user | `drop_dm_object_name(Processes)`] | stats count min(_time) as firstTime max(_time) as lastTime by dest process_name process_guid file_name file_path file_create_time user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_file_without_extension_in_critical_folder_filter`
The SPL above uses the following Macros:
windows_file_without_extension_in_critical_folder_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 Filesystem responsible for the changes from your endpoints into the
Endpoint datamodel in the
Known False Positives
Unknown at this point
Associated Analytic Story
|90.0||90||100||Driver file with out file extension drop in $file_path$ in $dest$|
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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replay.py tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 1