System Owner/User Discovery

Windows

Adversaries may attempt to identify the primary user, currently logged in user, set of users that commonly uses a system, or whether a user is actively using the system. They may do this, for example, by retrieving account usernames or by using Credential Dumping. The information may be collected in a number of different ways using other Discovery techniques, because user and username details are prevalent throughout a system and include running process ownership, file/directory ownership, session information, and system logs.

Mac

On Mac, the currently logged in user can be identified with users,w, and who.

Linux

On Linux, the currently logged in user can be identified with w and who.

ID: T1033

Tactic: Discovery

Platform:  Linux, macOS, Windows

Permissions Required:  User, Administrator

Data Sources:  File monitoring, Process monitoring, Process command-line parameters

CAPEC ID:  CAPEC-577

Version: 1.0

Mitigations

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

Examples

Name Description
Agent Tesla

Agent Tesla collects the username from the victim’s machine.[1][2]

Agent.btz

Agent.btz obtains the victim username and saves it to a file.[3]

APT19

APT19 used an HTTP malware variant and a Port 22 malware variant to collect the victim’s username.[4]

APT3

An APT3 downloader uses the Windows command "cmd.exe" /C whoami to verify that it is running with the elevated privileges of "System."[5]

APT32

APT32 collected the victim's username and executed the whoami command on the victim's machine.[6][7]

APT37

APT37 identifies the victim username.[8]

APT39

APT39 used Remexi to collect usernames from the system.[9]

Azorult

Azorult can collect the username from the victim’s machine.[10]

Backdoor.Oldrea

Backdoor.Oldrea collects the current username from the victim.[11]

BISCUIT

BISCUIT has a command to gather the username from the system.[12]

Cannon

Cannon can gather the username from the system.[13]

Cardinal RAT

Cardinal RAT can collect the username from a victim machine.[14]

DarkComet

DarkComet gathers the username from the victim’s machine.[15]

Denis

Denis collects the username from the victim’s machine.[16]

Derusbi

A Linux version of Derusbi checks if the victim user ID is anything other than zero (normally used for root), and the malware will not execute if it does not have root privileges. Derusbi also gathers the username of the victim.[17]

DownPaper

DownPaper collects the victim username and sends it to the C2 server.[18]

Dragonfly 2.0

Dragonfly 2.0 used the command query user on victim hosts.[19]

Epic

Epic collects the user name from the victim’s machine.[20]

Felismus

Felismus collects the current username and sends it to the C2 server.[21]

FELIXROOT

FELIXROOT collects the username from the victim’s machine.[22][23]

FIN10

FIN10 has used Meterpreter to enumerate users on remote systems.[24]

FlawedAmmyy

FlawedAmmyy enumerates the current user during the initial infection.[25]

Gamaredon Group

A Gamaredon Group file stealer can gather the victim's username to send to a C2 server.[26]

Gazer

Gazer obtains the current user's security identifier.[27]

Gold Dragon

Gold Dragon collects the endpoint victim's username and uses it as a basis for downloading additional components from the C2 server.[28]

GravityRAT

GravityRAT collects the victim username along with other account information (account type, description, full name, SID and status).[29]

HAPPYWORK

can collect the victim user name.[30]

HAWKBALL

HAWKBALL can collect the user name of the system.[31]

InvisiMole

InvisiMole lists local users and session information.[32]

Ixeshe

Ixeshe collects the username from the victim’s machine.[33]

JPIN

JPIN can obtain the victim user name.[34]

Kazuar

Kazuar gathers information on users.[35]

Koadic

Koadic can identify logged in users across the domain and views user sessions.[36]

Komplex

The OsInfo function in Komplex collects the current running username.[37]

KONNI

KONNI can collect the username from the victim’s machine.[38]

Kwampirs

Kwampirs collects registered owner details by using the commands systeminfo and net config workstation.[39]

Lazarus Group

Various Lazarus Group malware enumerates logged-on users.[40][41][42][43][44]

Linux Rabbit

Linux Rabbit opens a socket on port 22 and if it receives a response it attempts to obtain the machine's hostname and Top-Level Domain.[45]

Magic Hound

Magic Hound malware has obtained the victim username and sent it to the C2 server.[46]

Micropsia

Micropsia collects the username from the victim’s machine.[47]

MirageFox

MirageFox can gather the username from the victim’s machine.[48]

Mis-Type

Mis-Type runs tests to determine the privilege level of the compromised user.[49]

MoonWind

MoonWind obtains the victim username.[50]

More_eggs

More_eggs has the capability to gather the username from the victim's machine.[51]

Mosquito

Mosquito runs whoami on the victim’s machine.[52]

MuddyWater

MuddyWater has used malware that can collect the victim’s username.[53]

NanHaiShu

NanHaiShu collects the username from the victim.[54]

NDiskMonitor

NDiskMonitor obtains the victim username and encrypts the information to send over its C2 channel.[55]

njRAT

njRAT enumerates the current user during the initial infection.[56]

NOKKI

NOKKI can collect the username from the victim’s machine.[57]

Octopus

Octopus collects the username from the victim’s machine.[58]

OilRig

OilRig has run whoami on a victim.[59][60]

Patchwork

Patchwork collected the victim username and whether it was running as admin, then sent the information to its C2 server.[61][55]

PowerDuke

PowerDuke has commands to get the current user's name and SID.[62]

POWRUNER

POWRUNER may collect information about the currently logged in user by running whoami on a victim.[63]

Prikormka

A module in Prikormka collects information from the victim about the current user name.[64]

Pupy

Pupy can enumerate local information for Linux hosts and find currently logged on users for Windows hosts.[65]

QUADAGENT

QUADAGENT gathers the victim username.[66]

RATANKBA

RATANKBA runs the whoami and query user commands.[67]

Reaver

Reaver collects the victim's username.[68]

RedLeaves

RedLeaves can obtain information about the logged on user both locally and for Remote Desktop sessions.[69]

Remsec

Remsec can obtain information about the current user.[70]

Revenge RAT

Revenge RAT gathers the username from the system.[71]

RGDoor

RGDoor executes the whoami on the victim’s machine.[72]

RogueRobin

RogueRobin collects the victim’s username and whether that user is an admin.[73]

RTM

RTM can obtain the victim username and permissions.[74]

ServHelper

ServHelper will attempt to enumerate the username of the victim.[75]

Soft Cell

Soft Cell used whoami and query user to obtain information about the victim user.[76]

SpeakUp

SpeakUp uses the whoami command.[77]

SslMM

SslMM sends the logged-on username to its hard-coded C2.[78]

Stealth Falcon

Stealth Falcon malware gathers the registered user and primary owner name via WMI.[79]

SynAck

SynAck gathers user names from infected hosts.[80]

Sys10

Sys10 collects the account name of the logged-in user and sends it to the C2.[78]

T9000

T9000 gathers and beacons the username of the logged in account during installation. It will also gather the username of running processes to determine if it is running as SYSTEM.[81]

Tropic Trooper

Tropic Trooper used letmein to scan for saved usernames on the target system.[82]

Unknown Logger

Unknown Logger can obtain information about the victim usernames.[83]

UPPERCUT

UPPERCUT has the capability to collect the current logged on user’s username from a machine.[84]

VERMIN

VERMIN gathers the username from the victim’s machine.[85]

WINDSHIELD

WINDSHIELD can gather the victim user name.[86]

WINERACK

WINERACK can gather information on the victim username.[30]

WinMM

WinMM uses NetUser-GetInfo to identify that it is running under an "Admin" account on the local system.[78]

XAgentOSX

XAgentOSX contains the getInfoOSX function to return the OS X version as well as the current user.[87]

yty

yty collects the victim’s username.[88]

Zebrocy

Zebrocy gets the username from the system.[89]

zwShell

zwShell can obtain the name of the logged-in user on the victim.[90]

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 based on the information obtained.

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.

References

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