Accessibility Features

Prevent the execution of unauthorized or malicious code on systems by implementing application control, script blocking, and other execution prevention mechanisms. This ensures that only trusted and authorized code is executed, reducing the risk of malware and unauthorized actions. This mitigation can be implemented through the following measures: Application Control: - Use Case: Use tools like AppLocker or Windows Defender Application Control (WDAC) to create whitelists of authorized applications and block unauthorized ones. On Linux, use tools like SELinux or AppArmor to define mandatory access control policies for application execution. - Implementation: Allow only digitally signed or pre-approved applications to execute on servers and endpoints. (e.g., `New-AppLockerPolicy -PolicyType Enforced -FilePath "C:\Policies\AppLocker.xml"`) Script Blocking: - Use Case: Use script control mechanisms to block unauthorized execution of scripts, such as PowerShell or JavaScript. Web Browsers: Use browser extensions or settings to block JavaScript execution from untrusted sources. - Implementation: Configure PowerShell to enforce Constrained Language Mode for non-administrator users. (e.g., `Set-ExecutionPolicy AllSigned`) Executable Blocking: - Use Case: Prevent execution of binaries from suspicious locations, such as `%TEMP%` or `%APPDATA%` directories. - Implementation: Block execution of `.exe`, `.bat`, or `.ps1` files from user-writable directories. Dynamic Analysis Prevention: - Use Case: Use behavior-based execution prevention tools to identify and block malicious activity in real time. - Implemenation: Employ EDR solutions that analyze runtime behavior and block suspicious code execution.

To use this technique remotely, an adversary must use it in conjunction with RDP. Ensure that Network Level Authentication is enabled to force the remote desktop session to authenticate before the session is created and the login screen displayed. It is enabled by default on Windows Vista and later. (Citation: TechNet RDP NLA) If possible, use a Remote Desktop Gateway to manage connections and security configuration of RDP within a network. (Citation: TechNet RDP Gateway) Identify and block potentially malicious software that may be executed by an adversary with this technique by using whitelisting (Citation: Beechey 2010) tools, like AppLocker, (Citation: Windows Commands JPCERT) (Citation: NSA MS AppLocker) or Software Restriction Policies (Citation: Corio 2008) where appropriate. (Citation: TechNet Applocker vs SRP)

Operating System Configuration involves adjusting system settings and hardening the default configurations of an operating system (OS) to mitigate adversary exploitation and prevent abuse of system functionality. Proper OS configurations address security vulnerabilities, limit attack surfaces, and ensure robust defense against a wide range of techniques. This mitigation can be implemented through the following measures: Disable Unused Features: - Turn off SMBv1, LLMNR, and NetBIOS where not needed. - Disable remote registry and unnecessary services. Enforce OS-level Protections: - Enable Data Execution Prevention (DEP), Address Space Layout Randomization (ASLR), and Control Flow Guard (CFG) on Windows. - Use AppArmor or SELinux on Linux for mandatory access controls. Secure Access Settings: - Enable User Account Control (UAC) for Windows. - Restrict root/sudo access on Linux/macOS and enforce strong permissions using sudoers files. File System Hardening: - Implement least-privilege access for critical files and system directories. - Audit permissions regularly using tools like icacls (Windows) or getfacl/chmod (Linux/macOS). Secure Remote Access: - Restrict RDP, SSH, and VNC to authorized IPs using firewall rules. - Enable NLA for RDP and enforce strong password/lockout policies. Harden Boot Configurations: - Enable Secure Boot and enforce UEFI/BIOS password protection. - Use BitLocker or LUKS to encrypt boot drives. Regular Audits: - Periodically audit OS configurations using tools like CIS Benchmarks or SCAP tools. *Tools for Implementation* Windows: - Microsoft Group Policy Objects (GPO): Centrally enforce OS security settings. - Windows Defender Exploit Guard: Built-in OS protection against exploits. - CIS-CAT Pro: Audit Windows security configurations based on CIS Benchmarks. Linux/macOS: - AppArmor/SELinux: Enforce mandatory access controls. - Lynis: Perform comprehensive security audits. - SCAP Security Guide: Automate configuration hardening using Security Content Automation Protocol. Cross-Platform: - Ansible or Chef/Puppet: Automate configuration hardening at scale. - OpenSCAP: Perform compliance and configuration checks.

Restrict access to network resources, such as file shares, remote systems, and services, to only those users, accounts, or systems with a legitimate business requirement. This can include employing technologies like network concentrators, RDP gateways, and zero-trust network access (ZTNA) models, alongside hardening services and protocols. This mitigation can be implemented through the following measures: Audit and Restrict Access: - Regularly audit permissions for file shares, network services, and remote access tools. - Remove unnecessary access and enforce least privilege principles for users and services. - Use Active Directory and IAM tools to restrict access based on roles and attributes. Deploy Secure Remote Access Solutions: - Use RDP gateways, VPN concentrators, and ZTNA solutions to aggregate and secure remote access connections. - Configure access controls to restrict connections based on time, device, and user identity. - Enforce MFA for all remote access mechanisms. Disable Unnecessary Services: - Identify running services using tools like netstat (Windows/Linux) or Nmap. - Disable unused services, such as Telnet, FTP, and legacy SMB, to reduce the attack surface. - Use firewall rules to block traffic on unused ports and protocols. Network Segmentation and Isolation: - Use VLANs, firewalls, or micro-segmentation to isolate critical network resources from general access. - Restrict communication between subnets to prevent lateral movement. Monitor and Log Access: - Monitor access attempts to file shares, RDP, and remote network resources using SIEM tools. - Enable auditing and logging for successful and failed attempts to access restricted resources. *Tools for Implementation* File Share Management: - Microsoft Active Directory Group Policies - Samba (Linux/Unix file share management) - AccessEnum (Windows access auditing tool) Secure Remote Access: - Microsoft Remote Desktop Gateway - Apache Guacamole (open-source RDP/VNC gateway) - Zero Trust solutions: Tailscale, Cloudflare Zero Trust Service and Protocol Hardening: - Nmap or Nessus for network service discovery - Windows Group Policy Editor for disabling SMBv1, Telnet, and legacy protocols - iptables or firewalld (Linux) for blocking unnecessary traffic Network Segmentation: - pfSense for open-source network isolation