Helminth is a backdoor that has at least two variants - one written in VBScript and PowerShell that is delivered via a macros in Excel spreadsheets, and one that is a standalone Windows executable. ^[1]

ID: S0170

ⓘ

Type: MALWARE

ⓘ

Platforms: Windows

Contributors: Robert Falcone

Version: 1.1

Created: 16 January 2018

Last Modified: 28 March 2020

Techniques Used

Domain	ID		Name	Use
Enterprise	T1071	.001	Application Layer Protocol: Web Protocols	Helminth can use HTTP for C2.^[1]
		.004	Application Layer Protocol: DNS	Helminth can use DNS for C2.^[1]
Enterprise	T1119		Automated Collection	A Helminth VBScript receives a batch script to execute a set of commands in a command prompt.^[1]
Enterprise	T1547	.001	Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder	Helminth establishes persistence by creating a shortcut in the Start Menu folder.^[1]
		.009	Boot or Logon Autostart Execution: Shortcut Modification	Helminth establishes persistence by creating a shortcut.^[1]
Enterprise	T1115		Clipboard Data	The executable version of Helminth has a module to log clipboard contents.^[1]
Enterprise	T1059	.001	Command and Scripting Interpreter: PowerShell	One version of Helminth uses a PowerShell script.^[1]
		.003	Command and Scripting Interpreter: Windows Command Shell	Helminth can provide a remote shell. One version of Helminth uses batch scripting.^[1]
		.005	Command and Scripting Interpreter: Visual Basic	One version of Helminth consists of VBScript scripts.^[1]
Enterprise	T1132	.001	Data Encoding: Standard Encoding	For C2 over HTTP, Helminth encodes data with base64 and sends it via the "Cookie" field of HTTP requests. For C2 over DNS, Helminth converts ASCII characters into their hexadecimal values and sends the data in cleartext.^[1]
Enterprise	T1074	.001	Data Staged: Local Data Staging	Helminth creates folders to store output from batch scripts prior to sending the information to its C2 server.^[1]
Enterprise	T1030		Data Transfer Size Limits	Helminth splits data into chunks up to 23 bytes and sends the data in DNS queries to its C2 server.^[1]
Enterprise	T1573	.001	Encrypted Channel: Symmetric Cryptography	Helminth encrypts data sent to its C2 server over HTTP with RC4.^[1]
Enterprise	T1105		Ingress Tool Transfer	Helminth can download additional files.^[1]
Enterprise	T1056	.001	Input Capture: Keylogging	The executable version of Helminth has a module to log keystrokes.^[1]
Enterprise	T1027		Obfuscated Files or Information	The Helminth config file is encrypted with RC4.^[1]
Enterprise	T1069	.001	Permission Groups Discovery: Local Groups	Helminth has checked the local administrators group.^[2]
		.002	Permission Groups Discovery: Domain Groups	Helminth has checked for the domain admin group and Exchange Trusted Subsystem groups using the commands `net group Exchange Trusted Subsystem /domain` and `net group domain admins /domain`.^[2]
Enterprise	T1057		Process Discovery	Helminth has used Tasklist to get information on processes.^[2]
Enterprise	T1053	.005	Scheduled Task/Job: Scheduled Task	Helminth has used a scheduled task for persistence.^[3]
Enterprise	T1553	.002	Subvert Trust Controls: Code Signing	Helminth samples have been signed with legitimate, compromised code signing certificates owned by software company AI Squared.^[3]

Groups That Use This Software

ID	Name	References
G0049	OilRig	^[1]^[4]^[5]

Helminth

Enterprise Layer

Techniques Used

Groups That Use This Software

References