Preventing Lateral Movement In Your Network

The threat of lateral movement within networks poses a significant challenge. Most cyberattacks, regardless of their specific tactics, involve a series of stages. Understanding these stages and implementing effective mitigation strategies is crucial for preventing lateral movement and fortifying your network against external threats. 

In this comprehensive blog post, we explore the typical ways outsiders gain a foothold, the risks associated with lateral movement, and robust mitigation strategies, with a particular focus on the importance of segmented networks.

The Anatomy of Outsider Attacks

Almost all cyberattacks originate from external threat actors seeking to exploit vulnerabilities in network defenses. These threat actors employ a range of tactics, techniques, and procedures (TTPs) to infiltrate networks, gain unauthorized access, and move laterally within the environment.

Here are the most common stages of an outsider attack:

1. Initial Access: The attacker gains an initial foothold in the network, often through methods like phishing, exploiting software vulnerabilities, or leveraging compromised credentials.
2. Lateral Movement: Once inside the network, the attacker navigates laterally to explore and compromise additional systems, gradually escalating privileges.
3. Persistence: The attacker establishes persistence to maintain access even after initial compromises are detected or mitigated.
4. Data Exfiltration: The final stage involves exfiltrating sensitive data or carrying out the intended malicious actions.

These are the main ways outsiders gain a foothold in your organization’s network: 

• Phishing Attacks: Phishing remains a prevalent method for attackers to gain an initial foothold. Through deceptive emails, attackers trick users into clicking on malicious links, downloading infected attachments, or revealing sensitive information.
• Exploiting Software Vulnerabilities: Attackers exploit vulnerabilities in software, applications, or operating systems to gain unauthorized access. Unpatched systems become easy targets for those who are adept at identifying and exploiting these vulnerabilities.
• Compromised Credentials: The use of stolen or compromised credentials is a common tactic. Attackers may obtain login credentials through data breaches, phishing, or credential stuffing attacks, allowing them to masquerade as legitimate users.

Risks Associated with Lateral Movement 

Once inside the network, attackers seek to escalate their privileges, gaining increased access and control over systems. This enables them to move laterally with greater ease and compromise more critical assets.

Lateral movement poses a significant risk of data exposure. As attackers traverse the network, they may come across sensitive information, intellectual property, or personally identifiable information (PII) that can be exploited or exfiltrated.

Successful lateral movement increases the dwell time of attackers within the network. The longer an attacker remains undetected, the more damage they can inflict, making it challenging for organizations to contain and mitigate the impact.

6 Mitigation Strategies to Prevent Lateral Movement

1. Network Segmentation: Network segmentation is a fundamental strategy for preventing lateral movement. By dividing the network into isolated segments, organizations can contain the impact of a potential breach. Even if one segment is compromised, the lateral spread of the attack is limited.
2. Least Privilege Principle: Implementing the principle of least privilege ensures that users and systems have the minimum level of access required to perform their roles. This limits the potential for attackers to escalate privileges and move laterally within the network.
3. Network Monitoring and Anomaly Detection: Regularly monitoring network traffic and employing anomaly detection tools help identify suspicious activities indicative of lateral movement. Unusual patterns in data access or privilege escalation can trigger alerts, allowing for rapid response and mitigation.
4. Multi-Factor Authentication (MFA): MFA adds an additional layer of security by requiring users to provide multiple forms of identification. This mitigates the risk of compromised credentials and makes it more challenging for attackers to move laterally within the network.
5. Regular Patching and Updates: Keeping systems, applications, and software up-to-date is crucial for mitigating the risk of exploits through software vulnerabilities. Regular patching closes potential entry points, making it more challenging for attackers to gain a foothold.
6. Endpoint Security Solutions: Endpoint security solutions, including antivirus software and endpoint detection and response (EDR) tools, play a critical role in preventing lateral movement. These solutions detect and respond to suspicious activities on individual devices, minimizing the risk of compromise.

The Role of Segmented Networks in Mitigating Lateral Movement

Network segmentation involves dividing a network into smaller, isolated segments to enhance security and control. Each segment operates as a separate entity, reducing the potential impact of a security incident and limiting lateral movement.

Here are the 3 benefits of segmented networks:

• Containment of Threats: In the event of a breach, segmented networks contain the threat to the affected segment, preventing the rapid spread of the attack across the entire network.
• Granular Access Controls: Segmented networks allow organizations to implement granular access controls, specifying which segments can communicate with each other. This restricts the lateral movement of attackers.
• Enhanced Security Posture: Segmenting the network provides an additional layer of defense, making it more challenging for attackers to navigate and compromise multiple segments.

Follow these best practices when implementing network segmentation:   

• Define Segment Boundaries: Clearly define the boundaries of each network segment based on the organization’s structure, data sensitivity, and security requirements. This ensures that segmentation aligns with the organization’s specific needs.
• Leverage Virtual LANs (VLANs): Virtual LANs facilitate network segmentation by creating logically isolated networks within a physical network infrastructure. VLANs are particularly useful for implementing segmented networks in environments with limited physical infrastructure changes.
• Implement Zero Trust Segmentation (ZTS): Implementing ZTS is a best practice for segmented networks as it shifts the traditional security paradigm from trusting implicitly to verifying explicitly, ensuring that every user and device undergoes thorough authentication before accessing network resources. By adopting a Zero Trust approach, organizations can minimize the attack surface, restrict lateral movement, and enhance overall security posture in the face of evolving cyber threats.
• Regularly Review and Update Segmentation Policies: As the organization evolves and the threat landscape changes, regularly review and update segmentation policies. This ensures that the segmentation strategy remains effective in preventing lateral movement.

Preventing lateral movement is a paramount concern for organizations seeking to safeguard their networks. Understanding the stages of outsider attacks, the ways outsiders gain a foothold, and the associated risks provides the foundation for robust mitigation strategies. The implementation of network segmentation, particularly through segmented networks, emerges as a crucial defense mechanism, limiting lateral movement and enhancing overall security. By adopting a multi-faceted approach that incorporates best practices, organizations can fortify their defenses, mitigate risks, and maintain the integrity of their networks in the face of evolving cyber threats.