Block AppData, Temp and hardening Office by GPO

24 בMay 2017

תגיות:
אין תגובות

Hi everyone, these days are the hardest days we have been experiencing, so many attacks, some security breaches we found. accordingly, I want to share with you the policies you have to deploy and the highlight you have to take under your consideration for implementing.

Let’s begin because we have a lot of work!

Due to CryptoLocker, we need to ensure that we block the possibility to run executable files on Temp and AppData folders.

We can disallow it to any user and prevent to run execution file or 7z, RAR, Wz, files on App data by creating a new “Addition Rules” policy in Group Policy,

* Make sure you have no problem with Office installation.

Please follow the GPO you should apply:

Policies you might apply:

Path: %AppData%\*.exe

Security Level: Disallowed

Description: Don’t allow executables to run from %AppData%.

Block CryptoLocker executable in %LocalAppData%

Path if using Windows XP: %UserProfile%\Local Settings\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\*.exe

Security Level: Disallowed

Description: Don’t allow executables to run from %AppData%.

Block Zbot executable in %AppData%

Path: %AppData%\*\*.exe

Security Level: Disallowed

Description: Don’t allow executables to run from immediate subfolders of %AppData%.

Block Zbot executable in %LocalAppData%

Path if using Windows XP: %UserProfile%\Local Settings\*\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\*\*.exe

Security Level: Disallowed

Description: Don’t allow executables to run from immediate subfolders of %AppData%.

Block executables run from archive attachments opened with WinRAR:

Path if using Windows XP: %UserProfile%\Local Settings\Temp\Rar*\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\Temp\Rar*\*.exe

Security Level: Disallowed

Description: Block executables run from archive attachments opened with WinRAR.

Block executables run from archive attachments opened with 7zip:

Path if using Windows XP: %UserProfile%\Local Settings\Temp\7z*\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\Temp\7z*\*.exe

Security Level: Disallowed

Description: Block executables run from archive attachments opened with 7zip.

Block executables run from archive attachments opened with WinZip:

Path if using Windows XP: %UserProfile%\Local Settings\Temp\wz*\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\Temp\wz*\*.exe

Security Level: Disallowed

Description: Block executables run from archive attachments opened with WinZip.

Block executables run from archive attachments opened using Windows built-in Zip support:

Path if using Windows XP: %UserProfile%\Local Settings\Temp\*.zip\*.exe

Path if using Windows Vista/7/8: %LocalAppData%\Temp\*.zip\*.exe

Security Level: Disallowed

Download and install Office 2016 ADMX file into your GPO, download it from here:

https://www.microsoft.com/en-us/download/details.aspx?id=49030

How to add AMDX to GPO:

How to add ADMX or ADM file to Group Policy

Block Office Macro from running:

Microsoft Excel 2013/2016/ Excel Options/Security/Trust Center:

Add Office 2016 ADMX file and apply the following Policy:

Block macros from running in Office files from the Internet – Enabled

VBA Macro Notification Settings – Enabled

Microsoft Excel 2013/2016/ Excel Options/Security/Trust Center/Protected View:

Do not open files from the Internet zone in Protected View – Disabled

Do not open files in unsafe locations in Protected View – Disabled

Set document behavior if file validation fails – Enabled

Turn off Protected View for attachments opened from Outlook – Disabled

Microsoft Outlook 2013/2016/ Security/Trust Center:

Security setting for macros – Enabled

Security Level Always warn

Microsoft Word 2013/Word Options/Security/Trust Center

Block macros from running in Office files from the Internet – Enabled

VBA Macro Notification Settings – Enabled [Disable all with notification]

Microsoft Word 2013/2016/ Word Options/Security/Trust Center/Protected View

Do not open files from the Internet zone in Protected View – Disabled

Do not open files in unsafe locations in Protected View – Disabled

Turn off Protected View for attachments opened from Outlook –Disabled

According to this discussion, you can see that it is recommended to deploy ShowOLEPackageObj:

http://www.edugeek.net/forums/how-do-you-do/159149-cryptolocker-prevention-5.html

Deploy the registry key ShowOLEPackageObj, for your version(s) of Office, to silently disable OLE Package function in Outlook:

Hive HKEY_CURRENT_USER

Key path:

Software\Policies\Microsoft\office\15.0\outlook\security

Value name: ShowOLEPackageObj

Value type: REG_DWORD

Value data: 0x0 (0)

Apply once and do not reapply: Yes

Additionally, I would apply this policy:

Trusted location:

Microsoft Office 2013/2016/Security Settings/Trusted Center/trusted Location

Warning: These locations are used as a trusted source for opening files in Word, Excel, PowerPoint, Access, InfoPath, and Visio. Macros and ActiveX controls in these documents will execute without user warning. If you change or add a location make sure that the new location is secure.

ow to apply UAC:

http://pelegit.co.il/uac-configure-domain/

Remove Local Administrator thought Active Directory:

Manage Local Account users by PowerShell

Consider change Local Administrator name to different Name, it is possible to change it broadly entire domain:

https://technet.microsoft.com/en-us/library/cc747484(v=ws.10).aspx

In a bottom line.

You have all instructions, all scripts you need for protecting your organization just, take responsibility for your IT infrastructure and initiate internal projects.

I would check any policy into lab environment for some day before deploying it to the production environment.

I can’t guarantee it will avoid any type of ransom or any attack, as you’re experiencing right now what goes on and seeing that there are many many holes we must seal, easier and in safety, we are doing the best to complete our job as IT guys.

הוסף תגובה
facebook linkedin twitter email

Leave a Reply

Your email address will not be published. Required fields are marked *