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Jordan Drysdale & Kent Ickler // In this webcast, we demonstrate some standard methodologies utilized during an internal network review. We also discuss various tools used to test network defenses […] The post WEBCAST: Wrangling Internal Network Vulnerabilities appeared first on Black Hills Information Security, Inc..
Analysis Summary
# Best Practices: Wrangling Internal Network Vulnerabilities
## Overview
These practices focus on the methodologies, tools, and solutions used during internal network reviews to test defenses and address common vulnerabilities discovered within the network environment, particularly those related to Windows and Microsoft ecosystems.
## Key Recommendations
### Immediate Actions
1. **Perform Initial Reconnaissance:** Utilize standard internal network review methodologies immediately to map out the accessible network topology and identify initial potential targets or service endpoints.
2. **Inventory and Audit Active Directory (AD):** Immediately begin inventorying domain controllers, group policy objects (GPO), and user/computer accounts to establish a baseline for potential privilege escalation vectors.
### Short-term Improvements (1-3 months)
1. **Implement Data Loss Prevention (DLP) Monitoring:** Establish or refine DLP solutions to monitor and alert on sensitive data transfers across the internal network, especially sensitive configurations or credentials.
2. **Baseline PowerShell Execution Policies:** Review and enforce secure PowerShell execution policies across endpoints to restrict unauthorized scripting until a more comprehensive endpoint hardening plan is developed.
3. **Conduct Automated Vulnerability Scanning:** Deploy internal vulnerability scanners to identify easily exploitable configuration weaknesses on targeted systems (e.g., Windows servers, end-user machines).
### Long-term Strategy (3+ months)
1. **Comprehensive Group Policy Hardening:** Systematically review and clean up legacy, overly permissive, or conflicting Group Policies. Implement the principle of least privilege via GPOs for administrative access and system configurations.
2. **Implement Credential Protection:** Adopt modern Windows features to protect stored credentials (e.g., LAPS for local admin accounts, credential guard) to mitigate post-exploitation credential theft.
3. **Establish Continuous Monitoring:** Deploy a Security Operations Center (SOC) capability that leverages network traffic analysis and endpoint detection/response (EDR) solutions to detect abnormal internal reconnaissance (e.g., anomalous use of tools like BloodHound indicators).
## Implementation Guidance
### For Small Organizations
- **Focus on Essential Tooling:** Concentrate resources on auditing existing Microsoft configurations (GPOs, local security policies) rather than acquiring extensive, expensive security toolsuites immediately.
- **Prioritize Patch Management:** Ensure rigorous, timely patching of all internet-facing and critical internal servers (e.g., Domain Controllers) as an immediate risk reduction measure.
### For Medium Organizations
- **Deploy Network Visibility Tools:** Implement Network Detection and Response (NDR) or NetFlow analysis tools to gain visibility into lateral movement attempts and command-and-control (C2) traffic indicators.
- **Formalize Internal Penetration Testing:** Schedule regular (at least annually) internal penetration tests following established methodologies to validate defense effectiveness against known internal threat actors.
### For Large Enterprises
- **Integrate Attack Simulation:** Integrate advanced threat emulation focusing on techniques seen in real-world internal breaches, potentially utilizing frameworks like MITRE ATT&CK to test detection capabilities systematically.
- **Automate GPO Auditing and Remediation:** Utilize configuration management tools (e.g., Ansible, SCCM) or specialized tools to continuously audit GPO settings against a secure baseline, automatically creating ticketing for deviations.
- **Implement Privileged Access Management (PAM):** Deploy a robust PAM solution to vault, rotate, and manage administrative credentials, severely limiting the usefulness of credential theft techniques like Pass-the-Hash.
## Configuration Examples
*Note: Specific configuration details require referencing the tools mentioned (e.g., BloodHound, PowerSploit) or specific Microsoft documentation for precise syntax.*
| Area | Best Practice Focus | Mitigation Goal |
| :--- | :--- | :--- |
| **Group Policy** | Restrict administrative access to Domain Controllers; audit GPO inheritance paths. | Prevent domain-wide configuration compromise. |
| **Endpoint Security** | Employ PowerShell logging (Script Block Logging) and module logging. | Detect post-exploitation activity using native OS tools. |
| **Credential Storage** | Configure LAPS (Local Administrator Password Solution) for unique, managed local administrator passwords. | Eliminate lateral movement via compromised NTLM hash or shared credential. |
## Compliance Alignment
The recommended practices align with the defensive and identification mandates found within:
* **NIST Cybersecurity Framework (CSF):** Heavy focus on **Identify** (Asset Management, Risk Assessment) and **Protect** (Access Control, Data Security).
* **CIS Controls:** Directly addresses controls related to Inventory and Control of Assets, Account Management, and Auditing.
* **ISO/IEC 27001:** Related to Annex A controls concerning access control and operational security management.
## Common Pitfalls to Avoid
- **Ignoring Default Configurations:** Assuming default Microsoft/Windows server installations are secure.
- **Tool Over-reliance:** Relying solely on automated scanners without active testing of lateral movement paths (e.g., overlooking manual AD abuse methods visible in tools like BloodHound).
- **Inconsistent Patching:** Failing to enforce uniform vulnerability and patch management across the entire internal network, leaving low-hanging fruit for attackers.
- **Inadequate Logging Configuration:** Failing to enable verbose logging (especially PowerShell logging and detailed Windows Event Forwarding) required to trace attacker actions internally.
## Resources
- **Network Analysis Toolset:** Tools capable of deeper packet inspection and anomaly detection (e.g., RITA, mentioned in the source context, for behavioral analysis).
- **Active Directory Auditing:** Utilize open-source tools like BloodHound to map relationships and identify attack paths in Active Directory.
- **PowerShell Security:** Refer to Microsoft documentation for securing PowerShell execution environments and auditing scripts.
- **Training Resources:** Consult advanced courses focusing on "Defending the Enterprise" or "Assumed Compromise" methodologies for in-depth coverage of detection and response.