SOC Strategies for Detecting and Mitigating Lateral Movement in the Network

Introduction

Lateral movement is one of the most critical stages of the cyber kill chain, where adversaries who have gained access to your network attempt to explore and exploit different systems. Once an attacker reaches this stage, the key goal of your SOC team is to minimise their dwell time—the amount of time they spend within the network undetected.

This post will explore common techniques used by adversaries during lateral movement and how the Blue SOC team can detect and respond swiftly to mitigate damage.

The Anatomy of Lateral Movement

After an adversary successfully installs malicious software or exploits a vulnerability, they typically enter the lateral movement phase, where they attempt to:

• Perform network reconnaissance: Discovering network topology, servers, and identifying high-value targets.
• Harvest credentials: Extracting passwords and hashes, often looking for domain admin credentials.
• Query Active Directory: Running commands to find privileged accounts and key domain controllers (DCs).
• Connect to other systems: Using SSH, RDP, or SMB shares for unauthorised access.
• Deploy ransomware or destructware: Once lateral movement is complete, they may launch a ransomware attack.

Techniques Used by Attackers

Let’s break down the key techniques used during lateral movement:

1. Network Reconnaissance Adversaries will often issue commands like hostname, whoami, and ipconfig to gather information about the host. They will then attempt to fly under the radar of traditional IPS/EDR tools by using advanced methods.

2. Credential Harvesting Attackers may search for credentials in memory or use tools like Mimikatz to extract password hashes. If they are lucky, they may find a Domain Admin password in memory. Commands such as Cmdkey /l are used to list stored credentials.

3. Man-in-the-Middle (MitM) Attacks Adversaries often pose as legitimate corporate devices in stealth mode, capturing user credentials during legitimate authentication requests. This allows them to move across the network undetected.

4. Active Directory Reconnaissance Commands like Net GROUP “Domain Admins” and Net user “user” /domain are used to query AD and list the network’s privileged users. By issuing these queries, attackers gather valuable intelligence about their targets.

5. RDP/SSH/SMB Connections Attackers may utilise RDP, SSH, and SMB protocols to connect to other systems. Monitoring abnormal connections or access attempts can reveal these activities.

6. Destructive Malware In some cases, attackers use ransomware or destructware to cripple the network once they’ve navigated through your systems. Detection of ransomware indicators is critical to prevent widespread damage.

Command-line Indicators of Compromise

The following command-line actions are strong indicators that lateral movement is taking place:

• hostname, whoami, ipconfig
• Get-Process and ps “antivirus” | kill (trying to disable antivirus).
• NetSess.exe (domain enumeration), klist (Kerberos ticket hijacking).
• Net GROUP “Domain Admins” to enumerate domain administrators.
• Cmdkey /l to list currently stored credentials.

If these commands are detected, it's vital to treat the system as compromised and initiate an incident response process immediately.

Reducing Dwell Time with Proactive Defence

The primary mission of your SOC team is to reduce the adversary's dwell time. By continuously monitoring for telltale signs of lateral movement and using advanced threat-hunting techniques, your team can drastically reduce the time attackers have to navigate your network.

Proactive defence includes:

• Deploying advanced EDR solutions that monitor for suspicious command executions.
• Using MITRE ATT&CK techniques to map potential attack vectors.
• Monitoring network traffic for abnormal connections, such as unauthorised RDP or SMB sessions.
• Constantly improving your incident response playbooks by learning from past attack scenarios.

Conclusion

Lateral movement is a dangerous phase of any cyber attack, and it’s the responsibility of your Blue SOC team to identify and mitigate this activity quickly. By detecting abnormal behaviour early, and responding effectively, your organisation can minimise damage and prevent adversaries from gaining control of critical systems.