Unfurling Hemlock | |
Type of Malware | Exploit Kit |
Country of Origin | Russia |
Date of Initial Activity | 2023 |
Associated Groups | Unfurling Hemlock |
Motivation | Financial Gain |
Attack Vectors | Phishing |
Targeted Systems | Windows |
Overview
Unfurling Hemlock represents a formidable new threat identified by Outpost24’s KrakenLabs, employing a sophisticated “cluster bomb” malware distribution strategy. This Eastern European group has gained notoriety for deploying tens of thousands of malware samples using a multi-layered compression technique. Their approach involves distributing cabinet files named “WEXTRACT.EXE .MUI” that contain nested compressed files, each harboring various types of malicious software. This intricate method allows them to simultaneously deploy multiple malware variants, including stealers like Redline and Mystic Stealer, and loaders such as Amadey and SmokeLoader.
Targets
Individuals
How they operate
Initial Access and Execution
Unfurling Hemlock’s attack vector frequently begins with sophisticated phishing campaigns, designed to lure victims into executing malicious payloads. Phishing emails, often masked as legitimate communications, contain links or attachments that, when interacted with, deploy the initial malware. In some cases, the group utilizes drive-by compromise techniques, where malware is delivered via compromised websites or exploit kits. Upon successful initial access, Unfurling Hemlock leverages a range of execution techniques. The malware often employs scripting languages or command-line interfaces to run its payloads, ensuring that the malware is executed with the necessary privileges to further its objectives.
Persistence and Privilege Escalation
To maintain a foothold within the compromised environment, Unfurling Hemlock incorporates various persistence mechanisms. One common method involves modifying registry keys or startup folders to ensure that the malware reactivates after system reboots. Additionally, the malware can use techniques such as Windows Management Instrumentation (WMI) to execute commands or scripts persistently. Privilege escalation is another critical aspect of its operation, with the malware exploiting vulnerabilities within software or leveraging flaws in the operating system to gain elevated privileges. This escalation enables the malware to execute its payloads with higher permissions, expanding its control over the compromised system.
Defense Evasion and Credential Access
Unfurling Hemlock employs a suite of defense evasion techniques to avoid detection by traditional security measures. This includes obfuscation of its files and payloads to hinder analysis and detection. By using complex encoding and encryption methods, the malware ensures that its presence remains hidden from security tools. Additionally, the group often utilizes compression techniques to minimize the size of the payloads, further complicating detection efforts. Credential access is a focal point of Unfurling Hemlock’s strategy, with the malware designed to extract sensitive credentials from the system. This is achieved through credential dumping techniques that collect user credentials and authentication tokens, enabling further exploitation and lateral movement within the network.
Data Collection, Exfiltration, and Impact
Once inside the network, Unfurling Hemlock focuses on data collection and exfiltration. The malware stages collected data, preparing it for transmission to command and control servers. Data exfiltration often occurs through the same channel used for command and control communication, typically employing application layer protocols to blend in with legitimate traffic. The impact of Unfurling Hemlock extends beyond data theft, as the malware can also manipulate or delete data, disrupting normal operations and causing significant damage to the targeted organization.
MITRE Tactics and Techniques
Initial Access:
Phishing (T1566): The group may use phishing techniques to distribute malware or malicious payloads.
Drive-by Compromise (T1189): Malware may be delivered through compromised websites or exploit kits.
Execution:
Command and Scripting Interpreter (T1059): Executing malicious scripts or commands.
Windows Management Instrumentation (T1047): Using WMI for executing malware.
Persistence:
Registry Run Keys / Startup Folder (T1547.001): Establishing persistence by modifying startup settings.
Privilege Escalation:
Exploitation for Client Execution (T1203): Leveraging vulnerabilities in software to escalate privileges.
Defense Evasion:
Obfuscated Files or Information (T1027): Using obfuscation techniques to hide malware.
Compression (T1002): Compressing payloads to evade detection.
Credential Access:
Credential Dumping (T1003): Extracting credentials from the system.
Collection:
Data Staged (T1074): Collecting and staging data for exfiltration.
Command and Control:
Application Layer Protocol (T1071): Communicating with command and control servers using standard application protocols.
Exfiltration:
Exfiltration Over Command and Control Channel (T1041): Exfiltrating data through the same channel used for command and control.
Impact:
Data Manipulation (T1565): Altering or deleting data to disrupt operations.