Tag Archive: Defender ATP

Defender ATP EDR for MAC preview

During Microsoft Ignite, Microsoft announced Defender ATP EDR capabilities for Mac is available in preview.

It’s great to see Microsoft extends the EDR capabilities to cross-platform

  1. Rich investigation experience – including machine timeline, process creation, file creation, network connections and, of course, the popular Advanced Hunting.
  2. Optimized performance – enhanced CPU utilization in compilation procedures and large software deployments.
  3. In-context AV detections – just like with Windows, get insight into where a threat came from and how the malicious process or activity was created.

More information available at
https://techcommunity.microsoft.com/t5/Microsoft-Defender-ATP/Microsoft-Defender-ATP-for-Mac-EDR-in-Public-Preview/ba-p/985879

Happy Hunting!

Defender ATP to Linux – available next year

During Ignite Microsoft announces Defender ATP for Linux is coming next year

Extending Defender ATP to be able to natively support Windows, Mac and Linux is great news and will simplify advanced threat management across the environment.

Happy Hunting!

Advanced Hunting – Defender ATP – Squirrel

When working with Advanced Hunting in Defender ATP, you tend to always want to update your queries as you learn. You will probably also notice that sometimes your query wasn’t broad enough or all information was not available at the time. And sometimes you just want to make it look better for others to use in a shared environment.

We have updated the Squirrel hunting query to adjust to more parameters which can be used. we simple remove the check for a parameter and focus on the http part instead.

There are also some legit domains which are used by some of the applications, slack and discord to mention some of them.

ProcessCreationEvents
| where (ProcessCommandLine has "update.exe") or (ProcessCommandLine has "squirrel.exe")
| where (ProcessCommandLine contains "http")
| extend URL=extract(@"((http:|https:)+[^\s]+[\w])", 1, ProcessCommandLine)
| where URL !in ("https://slack.com/desktop/update/windows_x64", "https://discordapp.com/api/updates/stable")
| sort by EventTime desc 
| project EventTime, 
          ComputerName,
          URL,
          FolderPath, 
          ProcessCommandLine, 
          AccountName, 
          InitiatingProcessCommandLine, 
          ReportId, 
          ProcessId, 
          InitiatingProcessId

Happy Hunting!

Hunt for nuget/Squirrel update vulnerability

A few days ago, a post on medium stated that an arbitrary code execution was possible in Squirrel which affected Teams and other applications which used Squirrel and Nuget for updates.

https://medium.com/@reegun/nuget-squirrel-uncontrolled-endpoints-leads-to-arbitrary-code-execution-80c9df51cf12

In the post, Teams is mentioned as example but other affected application were mentioned on twitter.

So, to see what our environment is up to with regards to this. Our favorite place to go to: Defender ATP – Advanced Hunting!

To explain the query, since there are other apps than teams which uses Squirrel, we aim to keep the query as broad as we can.

Since some applications uses Squirrel and web for updates we can’t simply say that all web requests are malicious. But we have done some verification and discovered many apps vulnerable to this.

To make it more easy to overview we’re adding the URL to a column

To continue this we can count unique URL’s to find anomalies

Edit: An Updated Query can be found on the link below here http://blog.sec-labs.com/2019/07/advanced-hunting-defender-atp-squirrel/

ProcessCreationEvents
| where ProcessCommandLine has "update.exe"
| where (ProcessCommandLine contains "http") and (ProcessCommandLine contains "--update")
| extend exeURL = case(ProcessCommandLine has "=",split(ProcessCommandLine, "=", 1), 
                       ProcessCommandLine !has "=", split(ProcessCommandLine, "--update ",1), 
                       "Default")
| where exeURL != "Default"
| sort by EventTime desc 
|project EventTime, 
          ComputerName,
          exeURL,
          FolderPath, 
          ProcessCommandLine, 
          AccountName, 
          InitiatingProcessCommandLine, 
          ReportId, 
          ProcessId, 
          InitiatingProcessId

Defender Application Control would definitely block this attack and other mitigations in operating system will harden the clients in your environment.

Happy Hunting!

Hunting for USB Rubber Ducky/ Bad USB with ATP

Alright, so we’re here again with a hunting query to help catching some bad people out there.

This hunting started as a discussion with a customer and we figured out we should be able to chain the queries to see what happens after an event to be able to decide if it’s malicious or not.

Just to clear things out:
A USB Rubber Ducky is not something your AV solution would pick up. It’s a keyboard, it’s a preprogrammable keyboard. It exactly the same thing as plugging in a USB keyboard and type, except you’ve already told the keyboard what to type.

The ducky language is very simple as shown in below example

DELAY 3000
gui r
DELAY 100
STRING powershel xxxxxxxx
ENTER

The example will wait for 3 seconds, press win key and “r” and wait for another 100 ms and then type powershell xxxxxxx and then enter

USB rubber ducky

You encode the textfile to a binary and loads it to the flash memory inside (which is read by the rubber ducky, not by the device you connect it to) well you can make some changes to that, but in general and depending how you configure it.

Hunting USB devices

It’s easy to find the PnP event which could be headsets, mass storage devices, keyboards etc.

    MiscEvents
    | where ActionType == "PnpDeviceConnected"
    | extend parsed=parse_json(AdditionalFields)
    | sort by EventTime desc nulls last 
    | project 
        EventTime,
        ComputerName,
        DeviceDescription=tostring(parsed.DeviceDescription),
        ClassName=tostring(parsed.ClassName),
        DeviceId=tostring(parsed.VendorIds),
        VendorIds=tostring(parsed.VendorIds), MachineId , ReportId 

Mass storage devices

MiscEvents
| where ActionType == "PnpDeviceConnected"
| extend ParsedFields=parse_json(AdditionalFields)
| project ClassName=tostring(ParsedFields.ClassName), DeviceDescription=tostring(ParsedFields.DeviceDescription),
DeviceId=tostring(ParsedFields.DeviceId), VendorIds=tostring(ParsedFields.VendorIds), MachineId, ComputerName, EventTime
| where ClassName contains "drive" or ClassName contains "usb"
| where DeviceDescription contains "Mass Storage"

But idea to hunt for duckies is that we want to see what happens after the device load.

  • Device connected
  • Someone executes powershell or cmd within a certain amount of time (10 seconds)

To explain further

We gather all devices where action type is “PnpDeviceConnected” and where the device description is “HID Keyboard Device”

Then we gather process starts which contains powershell or cmd and then we compare the time for the event and only present the ones where the process start happened within 10 seconds after the device load event.

// Hunting for malicious HID Keyboard devices
// PNP Event and Powershell or CMD within 10 seconds after driver load
let MalPnPDevices =
    MiscEvents
    | where ActionType == "PnpDeviceConnected"
    | extend parsed=parse_json(AdditionalFields)
    | sort by EventTime desc nulls last 
    | where parsed.DeviceDescription == "HID Keyboard Device"
    | project PluginTime=EventTime, ComputerName,parsed.ClassName, parsed.DeviceId, parsed.DeviceDescription, AdditionalFields;
ProcessCreationEvents
| where ProcessCommandLine contains "powershell" or
        ProcessCommandLine startswith "cmd" 
| where isnotempty(ProcessCommandLine)         
| project ProcessCommandLine, ComputerName, EventTime, ReportId, MachineId
| join kind=inner MalPnPDevices on ComputerName
| where (EventTime-PluginTime) between (0min..10s)
| where ComputerName == ComputerName1

Of course, the 10 seconds is basically the Delay time. If an attacker sets 11 seconds, we would miss it. But this query would have to be trimmed for your environment.

There is also another thing, as an attacker, you would like to deliver the payload as quick as possible but still want the driver to be able to load.

I usually use between 3-6 seconds as initial payload for my duckies.

happy hunting ATP

You could also chain this with other events, like networkevents to discover network request after a specific event.

Happy Hunting!

Sec-Labs R&D

Defender ATP and PowerBI

Maybe, you don’t want management in the ATP portal, even though it’s configurable via roles, and maybe they don’t want to be there.

One thing I know is that most managers loves numbers, so why not provide them with a PowerBI report.

You can perfectly use cloud based option and there is an app for Windows Defender ATP already there for you to use.

Configure your connector and you’re all good to go

The dasboard looks like the following picture

With the many different tiles you, or your manager, can dig deeper in to events like in this following example with alert status

It’s also possible to filter data based on who a case was assigned to, who resolved the case etc.

If you have a PowerBI Pro account, you could subscribe to get scheduled reports.

You can also to quick filter

This is an easy win for your manager