Detectionmediumtest

Suspicious Copy From or To System Directory

Detects a suspicious copy operation that tries to copy a program from system (System32, SysWOW64, WinSxS) directories to another on disk. Often used to move LOLBINs such as 'certutil' or 'desktopimgdownldr' to a different location with a different name in order to bypass detections based on locations.

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Launch
Florian Roth (Nextron Systems), Markus Neis, Tim Shelton (HAWK.IO), Nasreddine Bencherchali (Nextron Systems)Created Fri Jul 03Updated Thu Nov 27fff9d2b7-e11c-4a69-93d3-40ef66189767windows
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 Logic5 selectors
detection:
    selection_img_cmd:
        Image|endswith: '\cmd.exe'
        CommandLine|contains: 'copy '
    selection_img_pwsh:
        Image|endswith:
            - '\powershell.exe'
            - '\pwsh.exe'
        CommandLine|contains:
            - 'copy-item'
            - ' copy '
            - 'cpi '
            - ' cp '
    selection_img_other:
        - Image|endswith:
              - '\robocopy.exe'
              - '\xcopy.exe'
        - OriginalFileName:
              - 'robocopy.exe'
              - 'XCOPY.EXE'
    selection_target:
        CommandLine|re|i: \s['"]?C:\\Windows\\(System32|SysWOW64|WinSxS)
    filter_optional_avira:
        Image|endswith: '\cmd.exe'
        CommandLine|contains|all:
            - '/c copy'
            - '\Temp\'
            - '\avira_system_speedup.exe'
        CommandLine|contains:
            - 'C:\Program Files\Avira\'
            - 'C:\Program Files (x86)\Avira\'
    condition: 1 of selection_img_* and selection_target and not 1 of filter_optional_*
False Positives

Depend on scripts and administrative tools used in the monitored environment (For example an admin scripts like https://www.itexperience.net/sccm-batch-files-and-32-bits-processes-on-64-bits-os/)

When cmd.exe and xcopy.exe are called directly

When the command contains the keywords but not in the correct order

Rule Metadata
Rule ID
fff9d2b7-e11c-4a69-93d3-40ef66189767
Status
test
Level
medium
Type
Detection
Created
Fri Jul 03
Modified
Thu Nov 27
Path
rules/windows/process_creation/proc_creation_win_susp_copy_system_dir.yml
Raw Tags
attack.defense-evasionattack.t1036.003
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