Remote Services: SMB/Windows Admin Shares

Adversaries may use Valid Accounts to interact with a remote network share using Server Message Block (SMB). The adversary may then perform actions as the logged-on user.

SMB is a file, printer, and serial port sharing protocol for Windows machines on the same network or domain. Adversaries may use SMB to interact with file shares, allowing them to move laterally throughout a network. Linux and macOS implementations of SMB typically use Samba.

Windows systems have hidden network shares that are accessible only to administrators and provide the ability for remote file copy and other administrative functions. Example network shares include C$, ADMIN$, and IPC$. Adversaries may use this technique in conjunction with administrator-level Valid Accounts to remotely access a networked system over SMB,[1] to interact with systems using remote procedure calls (RPCs),[2] transfer files, and run transferred binaries through remote Execution. Example execution techniques that rely on authenticated sessions over SMB/RPC are Scheduled Task/Job, Service Execution, and Windows Management Instrumentation. Adversaries can also use NTLM hashes to access administrator shares on systems with Pass the Hash and certain configuration and patch levels.[3]

ID: T1021.002
Sub-technique of:  T1021
Platforms: Windows
System Requirements: SMB enabled; Host/network firewalls not blocking SMB ports between source and destination; Use of domain account in administrator group on remote system or default system admin account.
Permissions Required: Administrator, User
Version: 1.0
Created: 11 February 2020
Last Modified: 23 March 2020
Provided by LAYER 8

Procedure Examples

ID Name Description
S0504 Anchor

Anchor can support windows execution via SMB shares.[4]

G0007 APT28

APT28 has mapped network drives using Net and administrator credentials.[5]

G0022 APT3

APT3 will copy files over to Windows Admin Shares (like ADMIN$) as part of lateral movement.[6]

G0050 APT32

APT32 used Net to use Windows' hidden network shares to copy their tools to remote machines for execution.[7]

G0087 APT39

APT39 has used SMB for lateral movement.[8]

G0096 APT41

APT41 has transferred implant files using Windows Admin Shares.[9]

S0089 BlackEnergy

BlackEnergy has run a plug-in on a victim to spread through the local network by using PsExec and accessing admin shares.[10]

G0108 Blue Mockingbird

Blue Mockingbird has used Windows Explorer to manually copy malicious files to remote hosts over SMB.[11]

G0114 Chimera

Chimera has used Windows admin shares to move laterally.[12][13]

S0154 Cobalt Strike

Cobalt Strike can use Window admin shares (C$ and ADMIN$) for lateral movement.[14]

S0608 Conficker

Conficker variants spread through NetBIOS share propagation.[15]

S0575 Conti

Conti can spread via SMB and encrypts files on different hosts, potentially compromising an entire network.[16][17]

G0009 Deep Panda

Deep Panda uses net.exe to connect to network shares using net use commands with compromised credentials.[18]

S0038 Duqu

Adversaries can instruct Duqu to spread laterally by copying itself to shares it has enumerated and for which it has obtained legitimate credentials (via keylogging or other means). The remote host is then infected by using the compromised credentials to schedule a task on remote machines that executes the malware.[19]

S0367 Emotet

Emotet leverages the Admin$ share for lateral movement once the local admin password has been brute forced. [20]

G0061 FIN8

FIN8 has attempted to map to C$ on enumerated hosts to test the scope of their current credentials/context.[21]

G0117 Fox Kitten

Fox Kitten has used valid accounts to access SMB shares.[22]

G0004 Ke3chang

Ke3chang actors have been known to copy files to the network shares of other computers to move laterally.[23][24]

S0236 Kwampirs

Kwampirs copies itself over network shares to move laterally on a victim network.[25]

G0032 Lazarus Group

Lazarus Group malware SierraAlfa accesses the ADMIN$ share via SMB to conduct lateral movement.[26][27]

S0532 Lucifer

Lucifer can infect victims by brute forcing SMB.[28]

S0039 Net

Lateral movement can be done with Net through net use commands to connect to the on remote systems.[29]

S0056 Net Crawler

Net Crawler uses Windows admin shares to establish authenticated sessions to remote systems over SMB as part of lateral movement.[30]

S0368 NotPetya

NotPetya can use PsExec, which interacts with the ADMIN$ network share to execute commands on remote systems.[31][32][33]

S0365 Olympic Destroyer

Olympic Destroyer uses PsExec to interact with the ADMIN$ network share to execute commands on remote systems.[34][33]

G0116 Operation Wocao

Operation Wocao has used Impacket's as well as accessing the C$ and IPC$ shares to move laterally.[35]

G0071 Orangeworm

Orangeworm has copied its backdoor across open network shares, including ADMIN$, C$WINDOWS, D$WINDOWS, and E$WINDOWS.[25]

S0029 PsExec

PsExec, a tool that has been used by adversaries, writes programs to the ADMIN$ network share to execute commands on remote systems.[33]

S0019 Regin

The Regin malware platform can use Windows admin shares to move laterally.[36]

S0446 Ryuk

Ryuk has used the C$ network share for lateral movement.[37]

G0034 Sandworm Team

Sandworm Team has run net use to connect to network shares.[38]

S0140 Shamoon

Shamoon accesses network share(s), enables share access to the target device, copies an executable payload to the target system, and uses a Scheduled Task/Job to execute the malware.[39]

S0603 Stuxnet

Stuxnet propagates to available network shares.[40]

G0028 Threat Group-1314

Threat Group-1314 actors mapped network drives using net use.[41]

G0010 Turla

Turla used net use commands to connect to lateral systems within a network.[42]

G0102 Wizard Spider

Wizard Spider has used SMB to drop Cobalt Strike Beacon on a domain controller for lateral movement.[43][44]

S0350 zwShell

zwShell has been copied over network shares to move laterally.[45]


ID Mitigation Description
M1037 Filter Network Traffic

Consider using the host firewall to restrict file sharing communications such as SMB. [46]

M1035 Limit Access to Resource Over Network

Consider disabling Windows administrative shares.

M1027 Password Policies

Do not reuse local administrator account passwords across systems. Ensure password complexity and uniqueness such that the passwords cannot be cracked or guessed.

M1026 Privileged Account Management

Deny remote use of local admin credentials to log into systems. Do not allow domain user accounts to be in the local Administrators group multiple systems.


ID Data Source Data Component
DS0017 Command Command Execution
DS0028 Logon Session Logon Session Creation
DS0033 Network Share Network Share Access
DS0029 Network Traffic Network Connection Creation
Network Traffic Flow

Ensure that proper logging of accounts used to log into systems is turned on and centrally collected. Windows logging is able to collect success/failure for accounts that may be used to move laterally and can be collected using tools such as Windows Event Forwarding. [47][48] Monitor remote login events and associated SMB activity for file transfers and remote process execution. Monitor the actions of remote users who connect to administrative shares. Monitor for use of tools and commands to connect to remote shares, such as Net, on the command-line interface and Discovery techniques that could be used to find remotely accessible systems.[49]


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