Forum Discussion
USB events
Hello, unfortunately I searched for some things and found only a few things about usb mounting that you can see in the defender reports.
I did a kql, but here at the company the usb is blocked and it doesn't work
kql takes the AdditionalField column and filters on everything that is removable.
DeviceEvents
|extend details = todynamic(AdditionalFields)
|mv-expand usb= details.IsOnRemovableMedia
| where tostring(usb) contains "true"
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Hello, unfortunately I searched for some things and found only a few things about usb mounting that you can see in the defender reports.
I did a kql, but here at the company the usb is blocked and it doesn't work
kql takes the AdditionalField column and filters on everything that is removable.
DeviceEvents
|extend details = todynamic(AdditionalFields)
|mv-expand usb= details.IsOnRemovableMedia
| where tostring(usb) contains "true"
if you liked it mark the answer with a like.
if you thought this answer helped in any way please mark it as best answer
Follow me: https://www.linkedin.com/in/raphael-custodio-soares/
- So I found another resource:
https://github.com/microsoft/Microsoft-365-Defender-Hunting-Queries/blob/master/Exfiltration/Files%20copied%20to%20USB%20drives.md
and by changing a few things, I now I have this:
DeviceEvents
| where ActionType=="UsbDriveMounted"
| extend ParsedFields=parse_json(AdditionalFields)
| project
MountTime=Timestamp,
DeviceName,
SerialNumber=ParsedFields.SerialNumber,
InitiatingProcessAccountName,
LoggedOnUsers=ParsedFields.LoggedOnUsers,
DriveLetter=ParsedFields.DriveLetter,
ProductName=ParsedFields.ProductName,
Manufacturer=ParsedFields.Manufacturer,
Volume=ParsedFields.Volume,
ReportId,
AdditionalFields
| where MountTime >= ago(24h)
| order by MountTime desc
This will search on any USB mounts in the last 24hrs and project certain fields from the AdditionalFields column.
To make it specific for my uses, I have added some properties of the specific USB device I am searching on, e.g.;
DeviceEvents
| where ActionType=="UsbDriveMounted"
| extend ParsedFields=parse_json(AdditionalFields)
| project
MountTime=Timestamp,
DeviceName,
SerialNumber=ParsedFields.SerialNumber,
InitiatingProcessAccountName,
LoggedOnUsers=ParsedFields.LoggedOnUsers,
DriveLetter=ParsedFields.DriveLetter,
ProductName=ParsedFields.ProductName,
Manufacturer=ParsedFields.Manufacturer,
Volume=ParsedFields.Volume,
ReportId,
AdditionalFields
| where MountTime >= ago(24h)
| where
(
SerialNumber contains "ENTER YOUR DETAILS HERE"
or Volume contains "ENTER YOUR DETAILS HERE"
or SerialNumber contains "ENTER YOUR DETAILS HERE"
or Volume contains "ENTER YOUR DETAILS HERE"
)
| order by MountTime desc
To get those details, I had to plug in a load of test USBs and run the first query and pull out the serial numbers and volume details. Annoyingly, not all of the USBs I tried had a serial number returned, so there was quite a lot of trial and error.
