Network Device CLI
Network Device CLI [T1059.008]
Information
Introduction
Network Device CLI (Command Line Interface) [T1059.008] is a sub-technique within the MITRE ATT&CK framework under the Execution tactic. Attackers leverage this method to execute commands directly on network devices such as routers, switches, and firewalls. By gaining access to the CLI, adversaries can manipulate device configurations, intercept network traffic, and maintain persistent control over network infrastructure. This technique is particularly critical due to the central role network devices play in managing data flow, security policies, and overall network availability and integrity.
Deep Dive Into Technique
Attackers typically execute commands directly on network devices through their native CLI interfaces. These interfaces are often accessed remotely using protocols like SSH, Telnet, or via serial console connections. Common devices targeted include routers, switches, firewalls, and load balancers from vendors such as Cisco, Juniper, Palo Alto Networks, Fortinet, and others.
Technical details and mechanisms involved include:
Remote Command Execution: Attackers often exploit weak credentials, default passwords, or vulnerabilities in device firmware to gain access to the CLI. Once authenticated, they can execute commands to alter device configurations, modify access control lists (ACLs), or redirect network traffic.
Configuration Manipulation: Commands executed through the CLI can modify critical configurations, such as routing tables, firewall rules, NAT settings, and VLAN assignments, enabling attackers to disrupt or intercept network traffic.
Persistence and Backdoor Creation: Attackers may add unauthorized user accounts, enable persistent access through SSH keys, or configure hidden administrative interfaces to maintain long-term access.
Data Exfiltration and Traffic Monitoring: CLI commands can facilitate packet captures, port mirroring, or logging modifications, enabling attackers to monitor, intercept, or exfiltrate sensitive network data.
Firmware and Software Manipulation: Attackers might use CLI access to install malicious firmware or software updates, providing additional covert methods of persistence and control.
When this Technique is Usually Used
Network Device CLI exploitation can occur across various stages of an attack lifecycle, including:
Initial Access: Exploiting default credentials or publicly known vulnerabilities to gain initial access to the network device.
Execution: Running commands directly on devices to alter configurations, disrupt services, or manipulate traffic flows.
Persistence: Establishing long-term access by adding hidden accounts, enabling SSH keys, or modifying configurations to ensure continued control.
Privilege Escalation: Moving from limited access to full administrative privileges by exploiting misconfigured permissions or vulnerabilities.
Defense Evasion: Modifying device logging, disabling security features, or altering audit trails to evade detection.
Collection and Exfiltration: Capturing network traffic, sensitive credentials, or configuration data and exfiltrating it through covert channels.
Impact: Causing denial-of-service (DoS) conditions, network outages, or unauthorized access to sensitive network segments.
Attack scenarios commonly involve:
Targeted cyber espionage operations aiming to intercept sensitive communications.
Advanced persistent threats (APT) maintaining long-term footholds within critical infrastructure.
Insider threats leveraging privileged access to network equipment for malicious intent.
Cybercriminals exploiting network devices to redirect traffic or carry out man-in-the-middle (MitM) attacks.
How this Technique is Usually Detected
Detection of malicious CLI activity on network devices involves a combination of monitoring, auditing, and anomaly detection techniques, including:
Logging and Audit Trails: Leveraging syslog, SNMP traps, or vendor-specific logging capabilities to capture command execution events, configuration changes, and login attempts.
Network Device Configuration Monitoring: Regularly auditing device configurations and comparing current states against known good baselines to detect unauthorized changes.
Behavioral Analysis and Anomaly Detection: Utilizing network monitoring tools (NetFlow analysis, IDS/IPS solutions, or SIEM platforms) to identify unusual command execution patterns, unexpected configuration changes, or abnormal traffic flows.
Authentication and Authorization Auditing: Monitoring for unusual login attempts, particularly from unknown sources, unusual IP addresses, or at abnormal times.
Indicator of Compromise (IoC) Identification: Identifying specific IoCs such as:
Unrecognized or unauthorized administrative accounts.
Unusual SSH/Telnet access patterns or login failures.
Unexpected configuration changes (e.g., new ACL entries, modified routing tables).
Suspicious firmware or software updates.
Unusual log deletions or log tampering attempts.
Tools commonly used for detection include:
Security Information and Event Management (SIEM) solutions (e.g., Splunk, IBM QRadar, Elastic Security).
Network configuration monitoring tools (e.g., SolarWinds Network Configuration Manager, Cisco Prime Infrastructure, Juniper Junos Space).
Intrusion Detection and Prevention Systems (IDS/IPS) (e.g., Snort, Suricata, Cisco Secure IPS).
Endpoint and network analytics platforms capable of detecting anomalous device behavior.
Why it is Important to Detect This Technique
Early detection of unauthorized CLI access and command execution on network devices is critical due to the significant impacts this technique can cause, including:
Network Disruption and Outages: Malicious configuration changes can lead to network downtime, reduced availability, and loss of critical services.
Data Breach and Exfiltration: Attackers may intercept and exfiltrate sensitive data traversing compromised network devices, leading to severe privacy and compliance implications.
Security Control Bypass: Attackers can disable or modify firewall rules, ACLs, and other security mechanisms, enabling unrestricted lateral movement and further exploitation.
Persistence and Long-Term Compromise: Undetected CLI access can allow attackers to maintain persistent footholds within critical network infrastructure, complicating incident response and remediation.
Reputational and Financial Damage: Successful exploitation of critical network devices can result in significant financial losses, regulatory penalties, and reputational harm to affected organizations.
Detecting this technique early ensures rapid containment, reduces potential damage, and improves overall organizational resilience against cyber threats.
Examples
Real-world examples of Network Device CLI sub-technique exploitation include:
Cisco IOS and IOS XE Attacks: Attackers exploiting CVE-2018-0171 (Smart Install vulnerability) to gain remote CLI access, modify configurations, and disrupt network operations. In 2018, attackers leveraged this vulnerability in widespread campaigns causing outages and unauthorized access to devices worldwide.
VPNFilter Malware Campaign: In 2018, VPNFilter malware infected routers globally, leveraging CLI access to manipulate configurations, intercept traffic, and exfiltrate sensitive data. The malware targeted devices from vendors such as Linksys, MikroTik, Netgear, and TP-Link.
APT41 Activity: Advanced Persistent Threat group APT41 used compromised credentials to access network device CLIs, enabling them to modify firewall rules, establish persistence, and exfiltrate sensitive data from multiple global organizations.
Juniper Networks Backdoor Incident (2015): Attackers inserted unauthorized code into Juniper ScreenOS firmware, providing hidden CLI access to VPN and firewall devices. This enabled covert surveillance, interception of encrypted VPN traffic, and long-term persistence.
Iranian APT Operations: Iranian threat actors have targeted network devices using default credentials and vulnerabilities to access CLIs, alter configurations, and redirect traffic for espionage purposes, particularly targeting critical infrastructure sectors.
These examples highlight the sophisticated nature of adversaries leveraging network device CLI access, underscoring the importance of robust security controls, monitoring, and detection capabilities.
Last updated
Was this helpful?