Obfuscated Files or Information: Fileless Storage

Adversaries may store data in "fileless" formats to conceal malicious activity from defenses. Fileless storage can be broadly defined as any format other than a file. Common examples of non-volatile fileless storage include the Windows Registry, event logs, or WMI repository.[1][2]

Similar to fileless in-memory behaviors such as Reflective Code Loading and Process Injection, fileless data storage may remain undetected by anti-virus and other endpoint security tools that can only access specific file formats from disk storage.

Adversaries may use fileless storage to conceal various types of stored data, including payloads/shellcode (potentially being used as part of Persistence) and collected data not yet exfiltrated from the victim (e.g., Local Data Staging). Adversaries also often encrypt, encode, splice, or otherwise obfuscate this fileless data when stored.

Some forms of fileless storage activity may indirectly create artifacts in the file system, but in central and otherwise difficult to inspect formats such as the WMI (e.g., %SystemRoot%\System32\Wbem\Repository) or Registry (e.g., %SystemRoot%\System32\Config) physical files.[1]

ID: T1027.011
Sub-technique of:  T1027
Tactic: Defense Evasion
Platforms: Windows
Contributors: Christopher Peacock; Denise Tan; Mark Wee; Simona David; Xavier Rousseau
Version: 1.0
Created: 23 March 2023
Last Modified: 04 May 2023

Procedure Examples

ID Name Description
G0050 APT32

APT32's backdoor has stored its configuration in a registry key.[3]

S0631 Chaes

Some versions of Chaes stored its instructions (otherwise in a instructions.ini file) in the Registry.[4]


CHOPSTICK may store RC4 encrypted configuration information in the Windows Registry.[5]

S0126 ComRAT

ComRAT has stored encrypted orchestrator code and payloads in the Registry.[6][7]

S0673 DarkWatchman

DarkWatchman can store configuration strings, keylogger, and output of components in the Registry.[8]

S0343 Exaramel for Windows

Exaramel for Windows stores the backdoor's configuration in the Registry in XML format.[9]

S0666 Gelsemium

Gelsemium can store its components in the Registry.[10]

S0531 Grandoreiro

Grandoreiro can store its configuration in the Registry at HKCU\Software\ under frequently changing names including %USERNAME% and ToolTech-RM.[11]

S0256 Mosquito

Mosquito stores configuration values under the Registry key HKCU\Software\Microsoft[dllname].[12]


NETWIRE can store its configuration information in the Registry under HKCU:\Software\Netwire.[13]

C0012 Operation CuckooBees

During Operation CuckooBees, the threat actors stroed payloads in Windows CLFS (Common Log File System) transactional logs.[14]

S0517 Pillowmint

Pillowmint has stored a compressed payload in the Registry key HKLM\SOFTWARE\Microsoft\DRM.[15]

S0501 PipeMon

PipeMon has stored its encrypted payload in the Registry under HKLM\SOFTWARE\Microsoft\Print\Components\.[16]

S0518 PolyglotDuke

PolyglotDuke can store encrypted JSON configuration files in the Registry.[17]

S0650 QakBot

QakBot can store its configuration information in a randomly named subkey under HKCU\Software\Microsoft.[18][19]


QUADAGENT stores a session identifier unique to the compromised system as well as a pre-shared key used for encrypting and decrypting C2 communications within a Registry key (such as HKCU\Office365DCOMCheck) in the HKCU hive.[20]

S0662 RCSession

RCSession can store its obfuscated configuration file in the Registry under HKLM\SOFTWARE\Plus or HKCU\SOFTWARE\Plus.[21][22]

S0511 RegDuke

RegDuke can store its encryption key in the Registry.[17]

S0496 REvil

REvil can save encryption parameters and system information in the Registry.[23][24][25][26][27]

S0596 ShadowPad

ShadowPad maintains a configuration block and virtual file system in the Registry.[28][29]

S0589 Sibot

Sibot has installed a second-stage script in the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\sibot registry key.[30]

S0663 SysUpdate

SysUpdate can store its encoded configuration file within Software\Classes\scConfig in either HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER.[31]

S0665 ThreatNeedle

ThreatNeedle can save its configuration data as a RC4-encrypted Registry key under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\GameCon.[32]

S0668 TinyTurla

TinyTurla can save its configuration parameters in the Registry.[33]

G0010 Turla

Turla has used the Registry to store encrypted and encoded payloads.[34][35]


TYPEFRAME can install and store encrypted configuration data under the Registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ShellCompatibility\Applications\laxhost.dll and HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\PrintConfigs.[36]

S0022 Uroburos

Uroburos can store configuration information for the kernel driver and kernel driver loader components in an encrypted blob typically found at HKLM:\SOFTWARE\Classes\.wav\OpenWithProgIds.[37]

S0476 Valak

Valak has the ability to store information regarding the C2 server and downloads in the Registry key HKCU\Software\ApplicationContainer\Appsw64.[38][39][40]

S0180 Volgmer

Volgmer stores an encoded configuration file in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\WMI\Security.[41][42]


ID Mitigation Description
M1047 Audit

Consider periodic review of common fileless storage locations (such as the Registry or WMI repository) to potentially identify abnormal and malicious data.


ID Data Source Data Component Detects
DS0024 Windows Registry Windows Registry Key Creation

Monitor for the creation of Registry values that may highlight storage of malicious data such as commands or payloads.

DS0005 WMI WMI Creation

Monitor for the creation of WMI Objects and values that may highlight storage of malicious data such as commands or payloads.


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