Lua

Detection Strategy for Lua Scripting Abuse

Limit Software Installation: Prevent users or groups from installing unauthorized or unapproved software to reduce the risk of introducing malicious or vulnerable applications. This can be achieved through allowlists, software restriction policies, endpoint management tools, and least privilege access principles. This mitigation can be implemented through the following measures:

Application Whitelisting

• Implement Microsoft AppLocker or Windows Defender Application Control (WDAC) to create and enforce allowlists for approved software.
• Whitelist applications based on file hash, path, or digital signatures.

Restrict User Permissions

• Remove local administrator rights for all non-IT users.
• Use Role-Based Access Control (RBAC) to restrict installation permissions to privileged accounts only.

Software Restriction Policies (SRP)

• Use GPO to configure SRP to deny execution of binaries from directories such as %AppData%, %Temp%, and external drives.
• Restrict specific file types (.exe, .bat, .msi, .js, .vbs) to trusted directories only.

Endpoint Management Solutions

• Deploy tools like Microsoft Intune, SCCM, or Jamf for centralized software management.
• Maintain a list of approved software, versions, and updates across the enterprise.

Monitor Software Installation Events

• Enable logging of software installation events and monitor Windows Event ID 4688 and Event ID 11707 for software installs.
• Use SIEM or EDR tools to alert on attempts to install unapproved software.

Implement Software Inventory Management

• Use tools like OSQuery or Wazuh to scan for unauthorized software on endpoints and servers.
• Conduct regular audits to detect and remove unapproved software.

Tools for Implementation

Application Whitelisting:

• Microsoft AppLocker
• Windows Defender Application Control (WDAC)

Endpoint Management:

• Microsoft Intune
• SCCM (System Center Configuration Manager)
• Jamf Pro (macOS)
• Puppet or Ansible for automation

Software Restriction Policies:

• Group Policy Object (GPO)
• Microsoft Software Restriction Policies (SRP)

Monitoring and Logging:

• Splunk
• OSQuery
• Wazuh (open-source SIEM and XDR)
• EDRs

Inventory Management and Auditing:

• OSQuery
• Wazuh

Audit: Auditing is the process of recording activity and systematically reviewing and analyzing the activity and system configurations. The primary purpose of auditing is to detect anomalies and identify potential threats or weaknesses in the environment. Proper auditing configurations can also help to meet compliance requirements. The process of auditing encompasses regular analysis of user behaviors and system logs in support of proactive security measures.

Auditing is applicable to all systems used within an organization, from the front door of a building to accessing a file on a fileserver. It is considered more critical for regulated industries such as, healthcare, finance and government where compliance requirements demand stringent tracking of user and system activates.This mitigation can be implemented through the following measures:

System Audit:

• Use Case: Regularly assess system configurations to ensure compliance with organizational security policies.
• Implementation: Use tools to scan for deviations from established benchmarks.

Permission Audits:

• Use Case: Review file and folder permissions to minimize the risk of unauthorized access or privilege escalation.
• Implementation: Run access reviews to identify users or groups with excessive permissions.

Software Audits:

• Use Case: Identify outdated, unsupported, or insecure software that could serve as an attack vector.
• Implementation: Use inventory and vulnerability scanning tools to detect outdated versions and recommend secure alternatives.

Configuration Audits:

• Use Case: Evaluate system and network configurations to ensure secure settings (e.g., disabled SMBv1, enabled MFA).
• Implementation: Implement automated configuration scanning tools like SCAP (Security Content Automation Protocol) to identify non-compliant systems.

Network Audits:

• Use Case: Examine network traffic, firewall rules, and endpoint communications to identify unauthorized or insecure connections.
• Implementation: Utilize tools such as Wireshark, or Zeek to monitor and log suspicious network behavior.

Execution Prevention: 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.