Detectionmediumtest
Files With System DLL Name In Unsuspected Locations
Detects the creation of a file with the ".dll" extension that has the name of a System DLL in uncommon or unsuspected locations. (Outisde of "System32", "SysWOW64", etc.). It is highly recommended to perform an initial baseline before using this rule in production.
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Launch
Nasreddine Bencherchali (Nextron Systems)Created Mon Jun 2413c02350-4177-4e45-ac17-cf7ca628ff5ewindows
Log Source
WindowsFile Event
ProductWindows← raw: windows
CategoryFile Event← raw: file_event
Events for file system activity including creation, modification, and deletion.
Detection Logic
Detection Logic2 selectors
detection:
selection:
TargetFilename|endswith:
# Note: Add more System DLL that can be abused for DLL sideloading to increase coverage
- '\secur32.dll'
- '\tdh.dll'
filter_main_generic:
# Note: It is recommended to use a more robust filter instead of this generic one, to avoid false negatives.
TargetFilename|contains:
# - '\SystemRoot\System32\'
- 'C:\$WINDOWS.~BT\'
- 'C:\$WinREAgent\'
- 'C:\Windows\SoftwareDistribution\'
- 'C:\Windows\System32\'
- 'C:\Windows\SysWOW64\'
- 'C:\Windows\WinSxS\'
- 'C:\Windows\uus\'
condition: selection and not 1 of filter_main_*False Positives
Third party software might bundle specific versions of system DLLs.
References
1
Resolving title…
Internal ResearchMITRE ATT&CK
Tactics
Sub-techniques
Rule Metadata
Rule ID
13c02350-4177-4e45-ac17-cf7ca628ff5e
Status
test
Level
medium
Type
Detection
Created
Mon Jun 24
Path
rules/windows/file/file_event/file_event_win_creation_system_dll_files.yml
Raw Tags
attack.defense-evasionattack.t1036.005