File With Suspicious Extension Downloaded Via Bitsadmin
A Sigma rule for process creation on Windows, by Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems).
high 3 ATT&CK techniques 1 program it names 1 everyday example trips it
What it looks for
detection:
selection_extension:
CommandLine|contains:
- '.7z'
- '.asax'
- '.ashx'
- '.asmx'
- '.asp'
- '.aspx'
- '.bat'
- '.cfm'
- '.cgi'
- '.chm'
- '.cmd'
- '.dll'
- '.gif'
- '.jpeg'
- '.jpg'
- '.jsp'
- '.jspx'
- '.log'
- '.png'
- '.ps1'
- '.psm1'
- '.rar'
- '.scf'
- '.sct'
- '.txt'
- '.vbe'
- '.vbs'
- '.war'
- '.wsf'
- '.wsh'
- '.xll'
- '.zip'
selection_flags:
CommandLine|contains:
- ' /transfer '
- ' /create '
- ' /addfile '
selection_img:
- Image|endswith: '\bitsadmin.exe'
- OriginalFileName: 'bitsadmin.exe'
condition: all of selection_*
The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.
Command lines that trip it
To add a file to the job on the page for bitsadmin addfile
bitsadmin /addfile myDownloadJob http://downloadsrv/10mb.zip c:\10mb.zipIdentifyThe commands LOLBAS or GTFOBins documents for bitsadmin.exe trip it too: each is on its program’s page, read by CmdID.