Remote System Discovery

Remote System Discovery [T1018]

Information

• Name: Remote System Discovery

• ID: T1018

• Tactics: TA0007

Introduction

Remote System Discovery is categorized under the MITRE ATT&CK framework as technique T1018. It involves adversaries attempting to discover information about remote systems and networks to identify potential targets and gather intelligence. Attackers commonly use this technique to map network infrastructure, enumerate live hosts, and gain insights into network topology and available resources. Remote system discovery is frequently a precursor technique, enabling further lateral movement, privilege escalation, or targeted exploitation.

Deep Dive Into Technique

Remote System Discovery involves several technical methods and mechanisms, including:

• Network Scanning:

  • Attackers use scanning tools like Nmap, Masscan, or Zmap to enumerate active hosts, open ports, and running services.

  • Scans can be stealthy (slow, randomized) or aggressive (fast, noisy), depending on the attacker’s objectives and operational security.

• Protocol Enumeration:

  • Attackers leverage protocols such as SMB, SNMP, LDAP, and NetBIOS to query remote systems and extract detailed information, including system names, operating system versions, domain memberships, and active services.

• Remote System Queries:

  • Utilizing built-in OS tools or commands:

    • Windows: net view, net group, net user, nbtstat, PowerShell cmdlets (Get-ADComputer, Get-NetComputer).

    • Linux/Unix: rpcinfo, showmount, smbclient, ldapsearch.

• Passive Discovery:

  • Attackers may passively monitor network traffic to identify active hosts, services, and infrastructure components without directly interacting with target systems.

• Cloud and Virtual Environment Discovery:

  • Attackers utilize cloud provider APIs (AWS, Azure, GCP) or virtualization management software (VMware, Hyper-V) APIs to enumerate virtual machines, containers, and cloud resources.

• Automation and Scripting:

  • Attackers often automate discovery processes using custom scripts, PowerShell, Python, or Bash scripts, enabling rapid enumeration and large-scale reconnaissance.

When this Technique is Usually Used

Remote System Discovery can appear at multiple stages of an attack lifecycle, including:

• Initial Access and Reconnaissance:

  • Attackers scan external-facing infrastructure to identify potential entry points, vulnerable services, and accessible systems.

• Post-Exploitation (Internal Reconnaissance):

  • After initial compromise, attackers enumerate internal networks to identify valuable targets, critical assets, and pivot points for lateral movement.

• Lateral Movement:

  • Attackers use remote discovery techniques to identify reachable systems, credentials reuse opportunities, and pathways for lateral traversal.

• Privilege Escalation and Persistence:

  • Attackers enumerate remote systems to identify privileged accounts, misconfigured services, or vulnerable endpoints to escalate privileges and establish persistence.

• Data Exfiltration and Impact:

  • Attackers discover remote systems containing sensitive data or critical infrastructure components to achieve objectives such as data theft, sabotage, or disruption.

How this Technique is Usually Detected

Detection methods and tools commonly employed to identify Remote System Discovery include:

• Network Monitoring and Intrusion Detection Systems (IDS):

  • Tools such as Snort, Suricata, Zeek, and Security Information and Event Management (SIEM) solutions can detect anomalous scanning activity, unusual protocol enumeration, or suspicious network queries.

• Endpoint Detection and Response (EDR):

  • EDR solutions detect anomalous command execution, suspicious scripts, and unusual network connections initiated from endpoints.

• Behavioral Analysis and Machine Learning:

  • Security analytics platforms leverage anomaly detection and machine learning models to detect abnormal patterns, such as unusual scanning behavior, spikes in network traffic, or atypical protocol usage.

• Logging and Monitoring:

  • Centralized logging of network devices, servers, and endpoints enables correlation and detection of enumeration commands such as:

    • Windows event logs (Security, System, Application logs).

    • Linux system logs (auth.log, syslog, auditd logs).

    • Firewall and router logs indicating scanning or probing behavior.

• Specific Indicators of Compromise (IoCs):

  • Unusual or repetitive network connections to multiple hosts/ports.

  • Execution of enumeration commands (net view, nbtstat, rpcinfo, ldapsearch).

  • Abnormal use of administrative tools and protocols (NetBIOS, SMB, SNMP).

  • Suspicious scripts or binaries on endpoints related to scanning tools (e.g., Nmap binaries, Masscan scripts).

Why it is Important to Detect This Technique

Early detection of Remote System Discovery is crucial due to its significant impacts on systems and networks:

• Early Attack Stage Identification:

  • Discovery activities often occur early in an attack lifecycle, providing defenders an opportunity to identify and mitigate threats before significant damage occurs.

• Preventing Lateral Movement:

  • Detection of discovery attempts helps prevent attackers from mapping internal networks, limiting their ability to move laterally and compromise additional systems.

• Reducing Risk of Data Exfiltration and Damage:

  • Identifying enumeration activities targeting sensitive data repositories or critical infrastructure helps organizations proactively protect valuable assets.

• Minimizing Operational Disruption:

  • Early detection enables rapid response, reducing risk of operational disruption, downtime, and financial losses resulting from successful attacks.

• Compliance and Regulatory Requirements:

  • Organizations subject to regulatory standards (PCI DSS, HIPAA, GDPR) must detect and respond to network reconnaissance activities to maintain compliance and avoid penalties.

Examples

Real-world examples demonstrating Remote System Discovery techniques, tools used, and their impacts include:

• NotPetya Ransomware Attack (2017):

  • Attack Scenario:

    • Attackers leveraged SMB and Windows administrative tools (net view, nbtstat) to enumerate network hosts and propagate ransomware rapidly across internal networks.

  • Tools Used:

    • SMB protocol enumeration, Windows built-in commands.

  • Impact:

    • Massive global disruption, billions of dollars in damages, operational downtime for numerous organizations.

• APT29 (Cozy Bear) Campaigns:

  • Attack Scenario:

    • Attackers performed extensive remote discovery using PowerShell scripts, LDAP queries, and network scanning to identify critical infrastructure and sensitive data repositories.

  • Tools Used:

    • PowerShell scripts, LDAP enumeration (ldapsearch), custom reconnaissance scripts.

  • Impact:

    • Theft of sensitive governmental and organizational data, prolonged undetected persistence, significant espionage implications.

• Mirai Botnet (IoT Malware):

  • Attack Scenario:

    • Mirai malware scanned the internet using automated scanning tools to identify vulnerable IoT devices for recruitment into a botnet.

  • Tools Used:

    • Automated scanning scripts, mass enumeration tools (Masscan, custom scripts).

  • Impact:

    • Large-scale Distributed Denial of Service (DDoS) attacks, widespread internet service disruptions, compromised IoT devices globally.

• Conti Ransomware Group:

  • Attack Scenario:

    • Conti attackers used network scanning tools, SMB enumeration, and Active Directory queries to map internal networks, identify backup systems, and locate critical data.

  • Tools Used:

    • Nmap, SMB enumeration tools, Active Directory enumeration scripts.

  • Impact:

    • Successful ransomware deployment, encryption of critical systems, significant financial and operational damages across multiple industries.