Identify and Eliminate Reconnaissance Threats

Reconnaissance threats are among the earliest stages of cyber-attacks, where adversaries attempt to map out network architecture and identify potential targets. Understanding and addressing these threats is essential for maintaining network security and resilience.

What Is a Recon Threat?

Definition: A reconnaissance (recon) threat refers to any activity or attempt to gather information about endpoints or network structure for the purpose of identifying vulnerabilities. This activity can be performed by both friendly and potentially harmful actors, ranging from legitimate network devices to adversaries with malicious intent.

What Is Reconnaissance?

Reconnaissance is the process of scanning or probing a network to collect information about active devices, their services, open ports, IP addresses, and network topology. It is a preliminary phase in which data is collected to understand the structure and weaknesses of a network.

Types of Reconnaissance:

• Passive Reconnaissance: Involves monitoring network traffic or gathering information without actively engaging with the network (e.g., sniffing network traffic).
• Active Reconnaissance: Entails direct interaction with network components, such as ping sweeps, port scanning, or service enumeration.

Why Do Friendly Devices Conduct Reconnaissance?

Friendly reconnaissance refers to legitimate network devices performing scans or queries for beneficial reasons, such as:

• Network Discovery: Devices such as routers, printers, or administrative systems often perform network discovery to identify available resources or validate connectivity.
• Service Location: Systems might need to locate services such as DHCP servers or network printers.
• Health Checks: Monitoring tools and software agents may scan endpoints to ensure devices are functioning properly and meet compliance standards.

Example: An IT management system regularly pings or scans devices to verify availability and uptime, facilitating maintenance and troubleshooting.

Why Do Frenemy Devices Conduct Reconnaissance?

Frenemy devices are devices that aren't inherently malicious but may conduct reconnaissance in ways that can create vulnerabilities or raise security concerns. Examples include:

• Smart TVs and IoT Devices: These devices often conduct discovery to connect with other smart devices or update their network maps. While their intentions may be benign, poorly secured devices can be manipulated or compromised to perform unwanted network scanning.
• Printers and VoIP Systems: Such devices might broadcast queries to identify connected endpoints, which could lead to unintentional exposure of network details if improperly configured.

Why It Matters: Although these devices may not be acting with malicious intent, their network behavior can open pathways for exploitation if attackers gain control over them.

Why Do Adversaries Conduct Reconnaissance?

Adversaries conduct reconnaissance for several strategic reasons:

• Identifying Vulnerabilities: Attackers use recon activities to identify unpatched systems, open ports, and vulnerable services that can be exploited.
• Mapping Network Topology: Understanding the layout of the network helps attackers pinpoint high-value targets and plan subsequent attack phases.
• Credential Harvesting: Reconnaissance can reveal weaknesses in user authentication processes or reveal unprotected credential exchanges.

Example: An attacker might use tools such as Nmap to scan for active devices and open ports, providing the initial groundwork for an exploitation attempt.

How to Accommodate Friendly Reconnaissance

Accommodating friendly reconnaissance ensures that legitimate network scans can continue to support business needs without exposing the network to undue risk:

• Device Whitelisting: Configure Ridgeback or network monitoring tools to recognize and allow expected queries from trusted devices.
• Scheduled Scans: Use scheduled or periodic scans that are monitored and approved to reduce noise and avoid false positives.
• Network Segmentation: Isolate devices that conduct regular discovery in controlled subnets to limit their scope and exposure.

Best Practice: Use access controls to ensure that only authenticated and approved devices can perform network queries.

How to Block Unfriendly Reconnaissance

Blocking unfriendly reconnaissance is critical to preventing attackers from gathering intelligence on your network:

A. Use Network Security Tools

• Intrusion Detection and Prevention Systems (IDPS): Deploy IDPS tools that can identify and block scanning activity, such as port scans or unusual bursts of ICMP traffic.
• Firewalls: Configure firewall rules to limit unnecessary traffic and prevent unauthorized devices from probing your network.
• Ridgeback: Leverage Ridgeback’s capabilities to monitor network traffic metadata for signs of unauthorized enumeration attempts and alert administrators in real-time.

B. Implement Network Access Controls

• Restrict Network Access: Limit access to sensitive parts of the network based on the principle of least privilege.
• MAC Address Filtering: Use MAC address filtering to restrict which devices can communicate on the network. There are advanced methods to use Ridgeback for network access control (NAC).
• Zero Trust Architecture: Adopt a zero-trust approach that authenticates and authorizes every device and connection request. There are advanced methods to use Ridgeback to implement zero trust policies appropriate for your network.

C. Employ Network Obfuscation Techniques

• Ridgeback: Use Ridgeback phantoms to overwhelm and entangle unauthorize reconnaissance processes.
• Honeypots and Decoy Systems: Deploy honeypots that mimic legitimate network assets to detect and divert malicious reconnaissance.
• Network Address Translation (NAT): Use NAT to obscure internal IP addresses and make endpoint enumeration more challenging for potential attackers.

Conclusion

Reconnaissance threats pose a significant risk to network security, serving as the precursor to more advanced attacks. While legitimate devices may perform necessary scans and queries, distinguishing between friendly, frenemy, and adversarial reconnaissance is essential for maintaining a secure network. By accommodating beneficial scans, restricting unwanted probing, and employing advanced monitoring tools like Ridgeback, you can build a network that is both functional and resilient against recon threats.