Sigma rule: EVTX Created In Uncommon Location

Rule

Title

EVTX Created In Uncommon Location

Status

test

Level

medium

Author

D3F7A5105

Date

2023-01-02

Modified

2026-10-13

File

rules/windows/file/file_event/file_event_win_create_evtx_non_common_locations.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of new files with the ".evtx" extension in non-common or non-standard location.
This could indicate tampering with default EVTX locations in order to evade security controls or simply exfiltration of event log to search for sensitive information within.
Note that backup software and legitimate administrator might perform similar actions during troubleshooting.

Log source

product

windows

category

file_event

definition

Requirements: The ".evtx" extension should be monitored via a Sysmon configuration. Example: <TargetFilename condition="end with">.evtx<TargetFilename>

Detection

selection:
    TargetFilename|endswith: '.evtx'
filter_main_path:
    TargetFilename|startswith: 'C:\Windows\System32\winevt\Logs\'
filter_main_baseimage:
    TargetFilename|startswith: 'C:\ProgramData\Microsoft\Windows\Containers\BaseImages\'
    TargetFilename|contains: '\Windows\System32\winevt\Logs\'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Administrator or backup activity
• An unknown bug seems to trigger the Windows "svchost" process to drop EVTX files in the "C:\Windows\Temp" directory in the form "<log_name">_<uuid>.evtx". See https://superuser.com/questions/1371229/low-disk-space-after-filling-up-c-windows-temp-with-evtx-and-txt-files

Tags

• attack.defense-impairment
• attack.t1685.001

MITRE ATT&CK ids this rule names

• T1685.001

References

• https://learn.microsoft.com/en-us/windows/win32/eventlog/eventlog-key

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_create_evtx_non_common_locations.yml