# Remote System Discovery

Remote System Discovery
Technique
ID T1018
Tactic Discovery
Platform Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1, Windows 10, MacOS, OS X
Data Sources Network protocol analysis, Process command-line parameters, Process monitoring, Process use of network

Adversaries will likely 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.

## Contents

### Windows

Examples of tools and commands that acquire this information include "ping" or "net view" using Net.

### Mac

Specific to Mac, the bonjour protocol to discover additional Mac-based systems within the same broadcast domain. Utilities such as "ping" and others can be used to gather information about remote systems.

### Linux

Utilities such as "ping" and others can be used to gather information about remote systems.

## Examples

• 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.1
• Turla surveys a system upon check-in to discover remote systems on a local network using the net view and net view /DOMAIN commands.2
• menuPass uses scripts to enumerate IP ranges on the victim network.3 menuPass has also issued the command net view /domain to a PlugX implant to gather information about remote systems on the network.4
• Cobalt Strike uses the native Windows Network Enumeration APIs to interrogate and discover targets in a Windows Active Directory network.5
• Commands such as net view can be used in Net to gather information about available remote systems.6
• Ping can be used to identify remote systems within a network.7
• Remsec can ping or traceroute a remote host.8
• SHOTPUT has a command to list all servers in the domain, as well as one to locate domain controllers on a domain.9
• Shamoon scans the C-class subnet of the IPs on the victim's interfaces.10
• Sykipot may use net view /domain to display hostnames of available systems on a network.11

## Mitigation

Identify unnecessary system utilities or potentially malicious software that may be used to acquire information on remotely available systems, and audit and/or block them by using whitelisting12 tools, like AppLocker,1314 or Software Restriction Policies15 where appropriate.16

## 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.