Protection of institutions against cyber attacks as recommended by NÚKIB

This article is primarily targeted at Czech state institutions and is based on recommendations of the Czech authority. However, the guidance and recommendations provided below can be applied to any organization.

The National Cyber and Information Security Agency published a warning against cyber threats targeting Czech state institutions and hospitals in particular. NÚKIB assesses this threat as high.

Activate phishing protection in Office 365

Office 365 offers advanced phishing protection within Office 365 Advanced Threat Protection.

In the Security & Compliance portal you can edit the default anti-phishing policy or create a new one. Under Threat Management – Policy, select Anti-phishing and edit the default policy or create a new one.

In Users to protect, select the users you want to explicitly protect against impersonation. Here, you should select users that are of some importance to your organization and could therefore most likely be targeted by attackers who impersonate those users. This is typically the management of an organization or IT department – CEO, CFO, CTO, CISO, etc.

Under Domains to protect, enable protection for all domains that you own. Optionally, you can explicitly set protection for external domains that are of some importance to your organization, such as key vendors or partners.

In the Actions section, you should choose to quarantine all emails detected as a domain or user impersonation.

Next, enable mailbox intelligence.

In the last step, you can optionally add trusted senders.

Next, enable antispoofing protection and set the policy as aggressive.

Report Message button in Outlook

The Report Message button allows users to report suspicious messages that can be analyzed by administrators in the Submissions section of the Security & Compliance Center.

In Services & add-ins, click Deploy add-in and in the Store, find the Report Message add-in. In Assigned users, select Everyone, and Deployment method select Fixed. Just click through the rest of the wizard.

Safe Attachments for advanced attachment protection

Safe Attachments is advanced attachment protection in Office 365 ATP. In the background of the service is done so-called detonation, where attachments in emails are executed and monitored what the attachments do. It detects if the attachments try to change any files, start services, stop services, connect to the Internet and download other files, exploit known bugs, etc. It is a very effective method of protection against zero-day vulnerabilities.

In the Security & Compliance Center, go to Threat Management – Policy and select Safe attachments. Check Turn on ATP for SharePoint, OneDrive, and Microsoft Teams at the top to protect users from malicious files in cloud services.

Create a new safe attachment policy that blocks malware-containing attachments and applies to all of your domains.

Safe Links for advanced link protection

Office 365 Safe Links is an advanced link protection service. Links in emails are replaced by a proxy address of the service that scans the target page for malicious code when it is clicked in real time.

In the Security & Compliance Center, go to Threat Management – Policy and select Safe Links. In the default organization-wide policy, check the use of safe links in Office 365 applications and prohibit users from clicking on the original URL.

Next, create a new Safe Links user policy to enable Safe Links. Next, enable integration with Teams, enable real-time scanning, and do not allow users to click through to the original URL. Apply the policy to all domains in your organization.

Advanced malware protection in Office 365

In the Security & Compliance Center, go to Threat Management – Policy and select Anti-malware. Modify the policy to allow Common attachment types filter and Malware zero-hour auto purge. In the Common attachment types filter, leave the default types of blocked files and verify or add at least the following – .exe, .msi, .bat, .cmd, .jar, .vbs, .ps1, .ps2.

Microsoft Defender Advanced Threat Protection

Microsoft Defender Advanced Protection is a highly advanced corporate security product based on free Windows Defender.

You need to create a workspace before you deploy Defender ATP. It is then possible to start onboarding computers and servers to Defender ATP. Onboarding is possible through Intune, Group Policy, System Center Configuration Manager or PowerShell script.

Within the recommended protection configuration, you should enable / enforce the following:

1. SmartScreen for Edge
2. SmartScreen for apps and files
3. Malicious site access
4. Unverified file download
5. Real-Time monitoring
6. Behavior monitoring
7. Network Inspection System
8. Cloud-delivered Protection
9. Attack Surface Reduction Rules (ASR) and block:
   • Office apps/macros creating executable content
   • Office apps launching child processes
   • Win32 imports from Office macro code
   • Obfuscated js/vbs/ps/macro code
   • js/vbs executing payload downloaded from Internet (no exceptions)
   • Executables that don’t meet a prevalence, age, or trusted list criteria
   • Execution of executable content (exe, dll, ps, js, vbs, etc.) dropped from email (webmail/mail client) (no exceptions)
10. Advanced Ransomware Protection
11. Network Protection
12. Tamper Protection

Enable file blocking in Microsoft Defender ATP

First, enable the Allow or block file feature in the Defender ATP. Go to Defender Security Center and go to Settings – Advanced features. Activate Allow or block file here.

Creating indicators for blocking hash files provided by NÚKIB

In its document, NÚKIB published a hash of seven files that should be blocked.

Add the above hashes to the Defender Security Center – Settings – Indicators.