Remote System Discovery

Adversaries may attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system. Functionality could exist within remote access tools to enable this, but utilities available on the operating system could also be used such as Ping or net view using Net. Adversaries may also use local host files (ex: C:\Windows\System32\Drivers\etc\hosts or /etc/hosts) in order to discover the hostname to IP address mappings of remote systems.

Specific to macOS, the bonjour protocol exists to discover additional Mac-based systems within the same broadcast domain.

Within IaaS (Infrastructure as a Service) environments, remote systems include instances and virtual machines in various states, including the running or stopped state. Cloud providers have created methods to serve information about remote systems, such as APIs and CLIs. For example, AWS provides a DescribeInstances API within the Amazon EC2 API and a describe-instances command within the AWS CLI that can return information about all instances within an account.^[1]^[2] Similarly, GCP's Cloud SDK CLI provides the gcloud compute instances list command to list all Google Compute Engine instances in a project, and Azure's CLI az vm list lists details of virtual machines.^[3]^[4]

ID: T1018

Sub-techniques: No sub-techniques

Tactic: Discovery

Platforms: AWS, Azure, GCP, Linux, Windows, macOS

Permissions Required: Administrator, SYSTEM, User

Data Sources: AWS CloudTrail logs, Azure activity logs, Network protocol analysis, Process command-line parameters, Process monitoring, Process use of network, Stackdriver logs

CAPEC ID: CAPEC-292

Contributors: Praetorian; RedHuntLabs, @redhuntlabs

Version: 2.1

Created: 31 May 2017

Last Modified: 26 May 2020

Version Permalink

Live Version

Procedure Examples

Name	Description
APT3	APT3 has a tool that can detect the existence of remote systems.^[19]^[31]
APT32	APT32 has enumerated DC servers using the command `net group "Domain Controllers" /domain`. The group has also used the `ping` command.^[32]
APT39	APT39 has used nbtscan and custom tools to discover remote systems. ^[39]^[40]^[41]
BRONZE BUTLER	BRONZE BUTLER typically use `ping` and Net to enumerate systems.^[34]
Carbon	Carbon uses the `net view` command.^[16]
Cobalt Strike	Cobalt Strike uses the native Windows Network Enumeration APIs to interrogate and discover targets in a Windows Active Directory network.^[7]
Comnie	Comnie runs the `net view` command
Deep Panda	Deep Panda has used ping to identify other machines of interest.^[28]
Dragonfly 2.0	Dragonfly 2.0 likely obtained a list of hosts in the victim environment.^[27]
Epic	Epic uses the `net view` command on the victim’s machine.^[11]
FIN5	FIN5 has used the open source tool Essential NetTools to map the network and build a list of targets.^[29]
FIN6	FIN6 used publicly available tools (including Microsoft's built-in SQL querying tool, osql.exe) to map the internal network and conduct reconnaissance against Active Directory, Structured Query Language (SQL) servers, and NetBIOS.^[26]
FIN8	FIN8 uses dsquery and other Active Directory utilities to enumerate hosts.^[35]
Ke3chang	Ke3chang has used network scanning and enumeration tools, including Ping.^[30]
Kwampirs	Kwampirs collects a list of available servers with the command `net view`.^[14]
Leafminer	Leafminer used Microsoft’s Sysinternals tools to gather detailed information about remote systems.^[38]
menuPass	menuPass uses scripts to enumerate IP ranges on the victim network. menuPass has also issued the command `net view /domain` to a PlugX implant to gather information about remote systems on the network.^[36]^[37]
MURKYTOP	MURKYTOP has the capability to identify remote hosts on connected networks.^[12]
Net	Commands such as `net view` can be used in Net to gather information about available remote systems.^[5]
njRAT	njRAT can identify remote hosts on connected networks.^[22]
Nltest	Nltest may be used to enumerate remote domain controllers using options such as `/dclist` and `/dsgetdc`.^[8]
Olympic Destroyer	Olympic Destroyer uses Windows Management Instrumentation to enumerate all systems in the network.^[20]
OSInfo	OSInfo performs a connection test to discover remote systems in the network^[19]
Ping	Ping can be used to identify remote systems within a network.^[6]
PoetRAT	PoetRAT used Nmap for remote system discovery.^[23]
RATANKBA	RATANKBA runs the `net view /domain` and `net view` commands.^[15]
Remsec	Remsec can ping or traceroute a remote host.^[18]
Rocke	Rocke has looked for IP addresses in the known_hosts file on the infected system and attempted to SSH into them.^[46]
Sandworm Team	Sandworm Team has used a tool to query Active Directory using LDAP, discovering information about computers listed in AD.^[47]
Shamoon	Shamoon scans the C-class subnet of the IPs on the victim's interfaces.^[13]
SHOTPUT	SHOTPUT has a command to list all servers in the domain, as well as one to locate domain controllers on a domain.^[10]
Silence	Silence has used Nmap to scan the corporate network, build a network topology, and identify vulnerable hosts.^[43]
Soft Cell	Soft Cell used a modified version of nbtscan to identify available NetBIOS name servers over the network as well as `ping` to identify remote systems.^[42]
Sykipot	Sykipot may use `net view /domain` to display hostnames of available systems on a network.^[17]
Threat Group-3390	Threat Group-3390 has used the `net view` command.^[25]
Turla	Turla surveys a system upon check-in to discover remote systems on a local network using the `net view` and `net view /DOMAIN` commands. Turla has also used `net group "Domain Computers" /domain`, `net group "Domain Controllers" /domain`, and `net group "Exchange Servers" /domain` to enumerate domain computers, including the organization's DC and Exchange Server.^[11]^[33]
USBferry	USBferry can use `net view` to gather information about remote systems.^[24]
WannaCry	WannaCry scans its local network segment for remote systems to try to exploit and copy itself to.^[21]
Wizard Spider	Wizard Spider has used networkdll for network discovery and psfin specifically for financial and point of sale indicators. Wizard Spider has also used `AdFind.exe` to enumerate domain computers, including the domain controller.^[44]^[45]
yty	yty uses the `net view` command for discovery.^[9]

Mitigations

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Detection

System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as Lateral Movement, based on the information obtained.

Normal, benign system and network events related to legitimate remote system discovery may be uncommon, depending on the environment and how they are used. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.

In cloud environments, the usage of particular commands or APIs to request information about remote systems may be common. Where possible, anomalous usage of these commands and APIs or the usage of these commands and APIs in conjunction with additional unexpected commands may be a sign of malicious use. Logging methods provided by cloud providers that capture history of CLI commands executed or API usage may be utilized for detection.

Remote System Discovery

Procedure Examples

Mitigations

Detection

References