--- title: "Fsutil Zeroing File" excerpt: "Indicator Removal on Host" categories: - Endpoint last_modified_at: 2021-08-11 toc: true toc_label: "" tags: - Indicator Removal on Host - Defense Evasion - Splunk Enterprise - Splunk Enterprise Security - Splunk Cloud - Endpoint --- [Try in Splunk Security Cloud](https://www.splunk.com/en_us/cyber-security.html){: .btn .btn--success} #### Description This search is to detect a suspicious fsutil process to zeroing a target file. This technique was seen in lockbit ransomware where it tries to zero out its malware path as part of its defense evasion after encrypting the compromised host. - **Type**: TTP - **Product**: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud - **Datamodel**: [Endpoint](https://docs.splunk.com/Documentation/CIM/latest/User/Endpoint) - **Last Updated**: 2021-08-11 - **Author**: Teoderick Contreras, Splunk - **ID**: 4e5e024e-fabb-11eb-8b8f-acde48001122 #### [ATT&CK](https://attack.mitre.org/) | ID | Technique | Tactic | | ----------- | ----------- |--------------- | | [T1070](https://attack.mitre.org/techniques/T1070/) | Indicator Removal on Host | Defense Evasion | #### Search ``` | tstats `security_content_summariesonly` count values(Processes.process) as process values(Processes.parent_process) as parent_process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=fsutil.exe Processes.process="*setzerodata*" by Processes.user Processes.process_name Processes.parent_process_name Processes.dest Processes.process Processes.parent_process | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `fsutil_zeroing_file_filter` ``` #### Associated Analytic Story * [Ransomware](/stories/ransomware) #### How To Implement To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. #### Required field * _time * Processes.user * Processes.process_name * Processes.parent_process_name * Processes.dest * Processes.process * Processes.parent_process #### Kill Chain Phase * Exploitation #### Known False Positives unknown #### RBA | Risk Score | Impact | Confidence | Message | | ----------- | ----------- |--------------|--------------| | 54.0 | 60 | 90 | Possible file data deletion on $dest$ using $process$ | #### Reference * [https://app.any.run/tasks/e0ac072d-58c9-4f53-8a3b-3e491c7ac5db/](https://app.any.run/tasks/e0ac072d-58c9-4f53-8a3b-3e491c7ac5db/) #### Test Dataset Replay any dataset to Splunk Enterprise by using our [`replay.py`](https://github.com/splunk/attack_data#using-replaypy) tool or the [UI](https://github.com/splunk/attack_data#using-ui). Alternatively you can replay a dataset into a [Splunk Attack Range](https://github.com/splunk/attack_range#replay-dumps-into-attack-range-splunk-server) * [https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1070/fsutil_file_zero/windows-sysmon.log](https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1070/fsutil_file_zero/windows-sysmon.log) [*source*](https://github.com/splunk/security_content/tree/develop/detections/endpoint/fsutil_zeroing_file.yml) \| *version*: **1**