Detectionhightest
Uncommon FileSystem Load Attempt By Format.com
Detects the execution of format.com with an uncommon filesystem selection that could indicate a defense evasion activity in which "format.com" is used to load malicious DLL files or other programs.
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Launch
Florian Roth (Nextron Systems)Created Tue Jan 04Updated Mon May 139fb6b26e-7f9e-4517-a48b-8cac4a1b6c60windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
Detection Logic
Detection Logic2 selectors
detection:
selection:
Image|endswith: '\format.com'
CommandLine|contains: '/fs:'
filter_main_known_fs:
CommandLine|contains:
- '/fs:exFAT'
- '/fs:FAT'
- '/fs:NTFS'
- '/fs:ReFS'
- '/fs:UDF'
condition: selection and not 1 of filter_main_*False Positives
Unknown
False positive likelihood has not been assessed. Additional context may be needed during triage.
MITRE ATT&CK
Tactics
Rule Metadata
Rule ID
9fb6b26e-7f9e-4517-a48b-8cac4a1b6c60
Status
test
Level
high
Type
Detection
Created
Tue Jan 04
Modified
Mon May 13
Path
rules/windows/process_creation/proc_creation_win_format_uncommon_filesystem_load.yml
Raw Tags
attack.defense-evasion