Identifying lateral movement in a network involves detecting suspicious activities and patterns as an attacker attempts to move from an initial compromised system to other valuable assets within the infrastructure.
What is Lateral Movement?
Lateral movement is a phase in a cyberattack where an attacker, having gained initial access to a network, navigates internally from the initial point of compromise to locate and compromise other systems, ultimately seeking their final target (e.g., domain controllers, critical databases, sensitive data).
Key Indicators of Lateral Movement
Attackers typically leave digital footprints as they move across systems. Monitoring for anomalies and specific patterns is crucial for detection.
Suspicious Login Activity
One of the most significant signs of lateral movement involves abnormal login attempts across different parts of the network.
Observing multiple login attempts across systems is a strong indicator of lateral movement. An attacker who has gained initial access to your network will try to expand their foothold. This often involves attempting to log into multiple systems, using either stolen credentials or brute force. These attempts might occur rapidly, from unexpected source systems, or outside typical working hours for the account being used.
Other login-related signs include:
- Failed Login Attempts: Numerous failed logins using the same or different credentials across various machines.
- Successful Logins from Unusual Sources: An account typically used on one server suddenly logging into many other servers or workstations.
- Logins at Unusual Times: Accounts logging in during off-hours or weekends without a legitimate business reason.
- Use of Default or Generic Accounts: Activity involving accounts that should be inactive or are rarely used.
- Credential Dumping: Evidence that tools designed to extract credentials from memory (like Mimikatz) have been run.
Unusual Network Connections
Attackers need to establish connections between machines to move laterally. Monitoring network traffic can reveal these connections.
- Connections between Unexpected Systems: Traffic flowing between machines that typically do not communicate with each other (e.g., a user workstation connecting directly to a critical server in a different segment).
- Use of Unusual Protocols: Services or protocols being used that are not standard for inter-system communication in your environment (e.g., excessive RDP connections originating from unusual sources, use of SMB for administrative tasks where it's not typical).
- High Volume of Traffic: A sudden spike in network traffic between two systems or segments.
- Connections to Administrative Shares: Accessing hidden administrative shares (like C$) on multiple machines.
Strange File and Process Activity
Lateral movement techniques often involve executing code or transferring files on remote systems.
- Remote Process Creation: Processes being created or executed on remote machines using tools like PsExec, Windows Management Instrumentation (WMI), or PowerShell Remoting.
- File Transfer to Unusual Locations: Administrative tools, hacking utilities, or malware samples being copied to temporary directories or system folders on multiple machines.
- Execution of Suspicious Commands: Running command-line tools or scripts remotely that are not part of normal administrative operations.
- Creation of Scheduled Tasks: Attackers often use scheduled tasks to maintain persistence and execute commands on target systems.
How to Monitor for Lateral Movement
Effective monitoring requires visibility across your network.
| Monitoring Area | Key Data Sources & Tools | What to Look For |
|---|---|---|
| Endpoint Activity | Endpoint Detection and Response (EDR), OS Security Logs | Process creation, file access, registry modifications, login attempts, command execution. |
| Network Activity | Network Intrusion Detection/Prevention Systems (NIDS/NIPS), Firewalls, NetFlow/IPFIX, Packet Capture | Unusual connections, traffic volumes, protocol usage, communication patterns. |
| Authentication | Security Event Logs (Windows Event ID 4624/4625/4648), Authentication Logs | Failed/successful logins, source/destination IP, user accounts, login type (network, interactive). |
| Log Aggregation | Security Information and Event Management (SIEM) Systems | Correlating events across multiple systems (e.g., same user failing logins on many machines). |
| Directory Services | Active Directory Logs | Account lockouts, password changes, group modifications, Kerberos ticket requests. |
By correlating alerts and logs from these different sources, security teams can build a picture of activity that might indicate an attacker moving across the network.
Why Identify Lateral Movement?
Detecting lateral movement early is critical because it represents an attacker escalating their privileges and getting closer to their objective. Early detection allows security teams to:
- Contain the breach before it spreads widely.
- Reduce the overall impact and potential damage.
- Understand the attacker's tactics, techniques, and procedures (TTPs) for future prevention.
- Minimize downtime and recovery costs.
Implementing robust logging, monitoring, and alert systems is essential for identifying and responding to lateral movement effectively.
