The Endpoint Security Checklist

Preventing Initial Compromise

The best defense against cyber attacks is to prevent attackers from gaining initial access to a machine in the first place.

VULNERABLE SOFTWARE

  • Patch What You Can
    • When vulnerabilities are disclosed, it’s only a matter of time before attackers begin exploiting them. Having a system in place to assess, test, and roll out patches is a vital first defense against attacks.
  • Isolate What You Can’t
    • Patching is vital, but not easy. Isolate systems you can’t patch quickly by restricting network access.

EXPOSED PORTS & SERVICES

  • Secure Remote Desktop (RDP)
    • Open ports with RDP exposed to the Internet are beacons for attackers. Restrict access to RDP listening ports by placing them behind a firewall and using a RDP Gateway.
    • Enabling network-level authentication and changing the default listening port (TCP 3389) is also recommended.
  • Secure Server Message Block (SMB)
    • Disable SMBv1 and use firewalls to restrict SMB network activity. WannaCry and other attacks leveraging the EternalBlue exploit have shown just how vulnerable organizations become when exposing SMB.

EMAIL

  • Block Common Malicious File Attachments
    • In addition to the obvious (.EXE, .BAT), consider blocking script files (.JS, .VBS, etc.), archive files (.ZIP, .SFX, .7z), and even Office files (.DOC, .DOCX, etc.) and PDFs.
  • Conduct User Awareness Training
    • Many attacks still initially require users clicking something they shouldn’t. Training and inform your end-users about attacks that rely on deception and social engineering.

BROWSERS

  • Utilize Ad-Blockers
    • Even legitimate websites can serve as infection points thanks to malvertising.

MICROSOFT OFFICE

  • Enforce Stricter Macro Controls
    • Block macros in Office files downloaded from the Internet. Macros are abused to download malware and launch malicious scripts.
  • Disable “Update Automatic Links At Open” in Microsoft Word
    • This will prevent abuse of the DDE feature (now disabled by default) and similar threats.
  • Disable OLE Packages
    • Considering the long history of attackers abusing Microsoft’s object linking and embedding (OLE) feature, it’s best disabled when possible.

Mitigating Post-Exploitation Techniques

Once attackers have access to a machine, they can evade detection by using fileless techniques and legitimate system administration tools to do their dirty work.

  • WHEN POWERSHELL ISN’T NECESSARY
    • Disable It
      • PowerShell is a powerful scripting framework that can provide attackers with a wide variety of dangerous functionality.
  • WHEN POWERSHELL IS NECESSARY
    • Update to Latest Version of PowerShell
      • It provides additional logging and updates to security features that can otherwise be bypassed on older versions (specifically version 2).
    • Block Unsigned PowerShell Scripts
      • While attackers can bypass this and other execution policy, attempts to do so can make attacks more visible.
    • Consider Using PowerShell Constrained Language Mode
      • It limits PowerShell to basic functionality, which will make many fileless attack techniques unusable.
    • Enable and Monitor Extended PowerShell Logging
      • Just be prepared for this to generate a lot of events. Tools like PowerShell Method Auditor can help process them.
  • SECURE & UTILIZE WINDOWS MANAGEMENT INSTRUMENTATION (WMI)
    • Create Defensive Permanent WMI Event Subscriptions
      • Its wide range of powerful admin capabilities make WMI a popular target of abuse, but they also make it a great tool for logging and responding to malicious activity.
  • If There’s No Need for Remote WMI
    • Consider setting up a fixed port for WMI and blocking it.
  • APPLY APPLICATION CONTROLS
    • Limit the Execution of Executables, DLLs, and Scripts with AppLocker
      • How restrictive you can be with whitelisting will depend on your organization’s needs.
  • Take Additional Steps to Harden AppLocker
    • As with any security measure, there are ways of bypassing AppLocker. Learn how to create rules to mitigate that risk.
  • APPLY LEAST PRIVILEGES & ACCESS CONTROLS
    • Exercise Least Privilege
      • As best practice, users should be given the bare minimum of access and privileges necessary, limiting the damage they can do if compromised.
  • When Possible, Use Highest UAC Enforcement Level
    • That includes setting UAC to “always notify,” which will trigger prompts whenever a program attempts to make changes to Windows settings or the machine.
  • Enable Admin Approval Mode
    • It enforces UAC for the built-in Administrator, which can help thwart privilege escalation and lateral movement attempts.
  • Remove Users from the Local Administrators Group
    • This can also help prevent privilege escalation attempts.
  • Disable Credential Caching
    • Don’t allow storage of credentials for network authentication. Anytime credentials are stored it presents attackers with an opportunity to grab them.
  • APPLY LEAST PRIVILEGES & ACCESS CONTROLS (CONTINUED)
    • Avoid Credential Overlap Across systems
      • This can help prevent lateral movement opportunities if valid credentials are obtained.
  • Avoid Staying Logged In On Remote Systems
    • Otherwise you open yourself up to attackers hijacking your admin access and privileges.
  • Disable Anonymous Login for Read and Write Access to Network File Shares (NFS)
    • Open shares provide a pivot point or means to further further spread an attack to other users on the network.
  • Disable Anonymous Login for Read and Write Access to File Transfer Protocol (FTP):
    • For the same reasons stated above for NFS.
  • Use Strong Passwords
    • Should go without saying, but obviously still a major common problem.
  • Utilize 2FA When Possible
    • Requiring two factor authentication can help keep attackers out even if they’ve successfully stolen passwords.
  • Apply Account Lockout Policies and/or Progressive Delays for Logins
    • This can help thwart brute force attempts.
  • MONITOR FOR
    • Changes In The Registry
      • Hiding scripts in the registry is one of the most common ways attackers gain persistence.
  • Suspicious WMI Activity
    • Creating defensive WMI subscription events.
  • Scheduled Task Creation
    • Scheduled tasks can be used to achieve persistence and escalate privileges. Monitor its creation.
  • Suspicious Processes and API Calls
    • Monitoring for specific calls in the PowerShell operational log can provide strong indication of attacks.
  • Processes Being Spawned with the CREATE_SUSPENDED flag
    • This is a good indication of process hollowing.

Conclusion

Endpoint Protection can prevent attacks from successfully launching by blocking fileless attacks, exploits, and file-based malware by analysing behaviours and attributes in the set-up phase of an attack – before damage is done.

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