Full Report
Read expert insights on how to strengthen your cybersecurity strategy with asset inventory and attack surface reduction.
Analysis Summary
# Best Practices: Attack Surface Reduction & Asset Inventory
## Overview
These practices address the fundamental need to identify, manage, and secure all organizational assets. By maintaining a comprehensive inventory and minimizing the "attack surface" (the sum of all points where an unauthorized user can try to enter or extract data), organizations can significantly reduce the likelihood of a successful breach and improve incident response efficiency.
## Key Recommendations
### Immediate Actions
1. **Conduct a Legacy Audit:** Identify and remove legacy remote access tools (e.g., old TeamViewer installations) that are no longer required for business operations.
2. **Disable High-Risk File Extensions:** Block or restrict the execution of high-risk file types used in phishing, such as `.iso`, `.img`, `.vhd`, and `.one` (OneNote) files, especially when downloaded from the internet.
3. **Disable Office Macros:** Ensure Microsoft Office macros are blocked for files originating from the internet, following current security defaults.
### Short-term Improvements (1-3 months)
1. **Baseline Asset Inventory:** Create a centralized registry of all physical/virtual systems, servers, and installed applications (e.g., VoIP software, print managers, file transfer tools).
2. **Service Hardening:** Audit all running services on active endpoints. Disable any service or port that does not directly support a documented business function.
3. **Vulnerability Mapping:** Map known vulnerabilities (like those seen in PaperCut or MOVEit) against your inventory to prioritize patching based on actual exposure.
### Long-term Strategy (3+ months)
1. **Automated Asset Discovery:** Implement tools that continuously scan the network to detect "shadow IT" or newly added devices in real-time.
2. **Hardening Lifecycle:** Integrate a system hardening checklist into the deployment process for all new servers and workstations.
3. **Staging Environment Security:** Apply the same security controls to staging and development environments as production, as these are frequent "side-door" targets for attackers.
## Implementation Guidance
### For Small Organizations
- **Focus on Visibility:** Use simple spreadsheets or basic network scanners to track what is on the network.
- **MSP Coordination:** If using a Managed Service Provider, request a formal report on legacy access tools they may have inherited or installed.
### For Medium Organizations
- **Application Control:** Move beyond hardware inventory to software inventory, tracking versions and patch levels for critical third-party apps (3CX, PaperCut, etc.).
- **Standardized Images:** Use hardened system images for all new employee devices to ensure consistent configuration.
### For Large Enterprises
- **SIEM/EDR Integration:** Feed asset inventory data into your SIEM/EDR to ensure alerts are contextualized (e.g., knowing if an alerted system contains sensitive data).
- **Segmented Staging:** Strictly isolate staging environments from production and ensure they do not contain live customer data.
## Configuration Examples
* **Email Gateway/Endpoint Policy:** Block incoming attachments with extensions `.iso`, `.vhd`, and `.vhd`.
* **Microsoft 365:** Enable the "Block macros from running in Office files from the Internet" policy via Group Policy or Intune.
* **Principle of Least Functionality:** Disable the "Print Spooler" service on any server that is not a designated print server.
## Compliance Alignment
- **CIS Controls:** Specifically Control 01 (Inventory and Control of Enterprise Assets) and Control 02 (Inventory and Control of Software Assets).
- **NIST CSF:** Aligns with the "Identify" (Asset Management) and "Protect" (Platform Hardening) functions.
- **ISO/IEC 27001:** Relates to A.8 (Asset Responsibility).
## Common Pitfalls to Avoid
- **Set-and-Forget Inventory:** Treating asset inventory as a one-time project rather than a continuous process.
- **Neglecting Staging:** Assuming staging or "dev" environments are safe to leave unpatched or unmonitored.
- **Ignoring Legacy Software:** Leaving "dormant" remote access tools installed "just in case," which provides attackers with a pre-installed backdoor.
## Resources
- **Huntress Blog:** hxxps[://]www[.]huntress[.]com/blog/system-hardening-checklist
- **Huntress Blog:** hxxps[://]www[.]huntress[.]com/blog/patch-management-strategy
- **NIST Framework:** hxxps[://]www[.]huntress[.]com/blog/breaking-down-the-nist-cybersecurity-framework
- **Backup Guidance:** 3-2-1 Backup Rule implementation hxxps[://]www[.]huntress[.]com/blog/3-2-1-backup-rule