Tag Archive: Defender

Hunting Windows Defender Exploit Guard with ATP

Alright, since I happen to be in a blog mode I keep the posts coming.

This post continue to explore the hunting capatibilities in Defender ATP by query for Exploit Guard detections.

So what’s this Exploit Guard?

Windows Defender Exploit Guard is a new set of intrusion prevention capabilities which are built-in with Windows 10, 1709 and newer versions.

Exploit Guard consists of 4 components which are designed to lock down the device against a wide variety of attack vectors and block behaviors commonly used in malware attacks, while enabling enterprises to balance their security risk and productivity requirements

ComponentDetails
Attack Surface Reduction (ASR)A set of controls that enterprises can enable to prevent malware from getting on the machine by blocking Office-, script-, and email-based threats
Network Protection Protects the endpoint against web-based threats by blocking any outbound process on the device to untrusted hosts/IP through Windows Defender SmartScreen
Controlled Folder AccessProtects sensitive data from ransomware by blocking untrusted processes from accessing your protected folders
Exploit ProtectionA set of exploit mitigations (replacing EMET) that can be easily configured to protect your system and applications

Example of ASR rules

• Block Office apps from creating executable content
• Block Office apps from launching child process
• Block Office apps from injecting into process
• Block Win32 imports from macro code in Office
• Block obfuscated macro code

Exploit Guard is configured through MDM (Intune) or SCCM or GPO’s or PowerShell.

If you have Microsoft 365 E5 license or Threat Protection license package, you don’t have to use Windows Event Forward to get the events in a central log solution. They will automatically be forwarded to your Microsoft 365 security portal https://security.microsoft.com where you have a nice looking dashboard where you can see alerts and configurations of ASR and other things.

This following dashboard is a part from the Monitor and Report section in the portal

Back to Defender ATP and the hunting which this post was supposed to be all about.

We have published some posts now about hunting custom alerts.

In the query console in Defender ATP we started to go backwards to find the ASR events. It’s simple. configure your client, run a few attacks which will trigger the alerts.

We looked in the MiscEvents for all events (filtered on computername and time). Which gaves us ideas of ActionTypes to use in the query.

Examples from the output:

AsrOfficeMacroWin32ApiCallsAudited
AsrPsexecWmiChildProcessBlocked
ControlledFolderAccessViolationBlocked
ExploitGuardAcgAudited
ExploitGuardChildProcessAudited
ExploitGuardNetworkProtectionBlocked
ExploitGuardNonMicrosoftSignedAudited
ExploitGuardWin32SystemCallBlocked
SmartScreenAppWarning
SmartScreenUrlWarning
SmartScreenUserOverride

Interesting note “SmartScreenUserOverride” is a separate event which you can query

When we had the raw Actiontypes we created the query to cover as much as we could.

//Happy Hunting
MiscEvents 
| where ActionType contains "asr" or
        ActionType contains "Exploit" or
        ActionType contains "SmartScreen" or
        ActionType contains "ControlledFolderAccess"
| extend JsonOut = parse_json(AdditionalFields)
| sort by EventTime desc 
| project EventTime, ComputerName, InitiatingProcessAccountName, ActionType,  
         FileName, FolderPath, RemoteUrl, ProcessCommandLine, InitiatingProcessCommandLine,
         JsonOut.IsAudit,JsonOut.Uri,JsonOut.RuleId,JsonOut.ActivityId
         

We are also parsing AdditionalFields to be able to add extra value to events which contained such data.

From this point we can do additional filters. For example, if you want to enable ASR enterprise wide, set them in auditmode and report on the alerts without affect user productivity, remediate and the do a enterprise wide block enrollment

Happy Hunting!

Onboarding older Windows Versions to WD ATP

Today Microsoft announced  that it’s now possible to onboard older legacy operatingsystems to ATP (Advanced Threat Protection) when the public preview that is available.

  • Windows 7 SP1 Enterprise
  • Windows 7 SP1 Pro
  • Windows 8.1 Pro
  • Windows 8.1 Enterprise

Even though we Always recommend using the latest versions there might be scenarios where you need the advanced detection and response capatibilities and  of ATP and it’s not possible to upgrade the machines.

The difference between Windows 10 and the older versions is that is not built-in and you have to install an Microsoft Monitoring agent which will connect to your workspace and report the sensor data.

Installing the agent

64-bit agent is available here:
https://go.microsoft.com/fwlink/?LinkId=828603

32-bit agent is available here:
https://go.microsoft.com/fwlink/?LinkId=828604

When you have downloaded the setup file you extract it using “/c” parameter

Install command
setup.exe /qn NOAPM=1 ADD_OPINSIGHTS_WORKSPACE=1 OPINSIGHTS_WORKSPACE_AZURE_CLOUD_TYPE=0 OPINSIGHTS_WORKSPACE_ID= OPINSIGHTS_WORKSPACE_KEY= AcceptEndUserLicenseAgreement=1

The workspace ID and Key is available in your ATP Portal https://securitycenter.windows.com

 

The clients will connect to the service using HTTPS and can be a direct connection or through a proxy or OMS gateway.

Agent Resource Ports
*.oms.opinsights.azure.com 443
*.blob.core.windows.net 443
*.azure-automation.net 443
*.ods.opinsights.azure.com 443
winatp-gw-cus.microsoft.com 443
winatp-gw-eus.microsoft.com 443
winatp-gw-neu.microsoft.com 443
winatp-gw-weu.microsoft.com 443
winatp-gw-uks.microsoft.com 443
winatp-gw-ukw.microsoft.com 443

 

When your clients are configured you should start seeing them in the ATP console

As you may have noticed there’s a link to Azure ATP alerts where you can dig further on advanced attacks in your environment.

On the following link you can find more information about onboarding older Windows Versions to Defender ATP
https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-atp/onboard-downlevel-windows-defender-advanced-threat-protection

Happy Hunting

 

/SEC-LABS R&D