Malware HUI Loader

HUI Loader is a custom DLL loader that has been used since at least 2015 by China-based threat groups including Cinnamon Tempest and menuPass to deploy malware on compromised hosts. HUI Loader has been observed in campaigns loading SodaMaster, PlugX, Cobalt Strike, Komplex, and several strains of ransomware.

Platforms : Windows
Version : 1.0
Created : 22 December 2023
Last Modified : 02 January 2024

List of techniques used :

id	description
T1140	Deobfuscate/Decode Files or Information Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system. One such example is the use of certutil to decode a remote access tool portable executable file that has been hidden inside a certificate file. Another example is using the Windows copy /b command to reassemble binary fragments into a malicious payload. Sometimes a user's action may be required to open it for deobfuscation or decryption as part of User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary.
T1562.006	Impair Defenses: Indicator Blocking An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting or even disabling host-based sensors, such as Event Tracing for Windows (ETW), by tampering settings that control the collection and flow of event telemetry. These settings may be stored on the system in configuration files and/or in the Registry as well as being accessible via administrative utilities such as PowerShell or Windows Management Instrumentation. For example, adversaries may modify the `File` value in HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesEventLogSecurity to hide their malicious actions in a new or different .evtx log file. This action does not require a system reboot and takes effect immediately. ETW interruption can be achieved multiple ways, however most directly by defining conditions using the PowerShell Set-EtwTraceProvider cmdlet or by interfacing directly with the Registry to make alterations. In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process responsible for forwarding telemetry and/or creating a host-based firewall rule to block traffic to specific hosts responsible for aggregating events, such as security information and event management (SIEM) products. In Linux environments, adversaries may disable or reconfigure log processing tools such as syslog or nxlog to inhibit detection and monitoring capabilities to facilitate follow on behaviors .
T1574.001	Hijack Execution Flow: DLL Search Order Hijacking Adversaries may execute their own malicious payloads by hijacking the search order used to load DLLs. Windows systems use a common method to look for required DLLs to load into a program. Hijacking DLL loads may be for the purpose of establishing persistence as well as elevating privileges and/or evading restrictions on file execution. There are many ways an adversary can hijack DLL loads. Adversaries may plant trojan dynamic-link library files (DLLs) in a directory that will be searched before the location of a legitimate library that will be requested by a program, causing Windows to load their malicious library when it is called for by the victim program. Adversaries may also perform DLL preloading, also called binary planting attacks, by placing a malicious DLL with the same name as an ambiguously specified DLL in a location that Windows searches before the legitimate DLL. Often this location is the current working directory of the program. Remote DLL preloading attacks occur when a program sets its current directory to a remote location such as a Web share before loading a DLL. Phantom DLL hijacking is a specific type of DLL search order hijacking where adversaries target references to non-existent DLL files. They may be able to load their own malicious DLL by planting it with the correct name in the location of the missing module. Adversaries may also directly modify the search order via DLL redirection, which after being enabled (in the Registry and creation of a redirection file) may cause a program to load a different DLL. If a search order-vulnerable program is configured to run at a higher privilege level, then the adversary-controlled DLL that is loaded will also be executed at the higher level. In this case, the technique could be used for privilege escalation from user to administrator or SYSTEM or from administrator to SYSTEM, depending on the program. Programs that fall victim to path hijacking may appear to behave normally because malicious DLLs may be configured to also load the legitimate DLLs they were meant to replace.

List of groups using the malware :

id	description
G0045	menuPass menuPass is a threat group that has been active since at least 2006. Individual members of menuPass are known to have acted in association with the Chinese Ministry of State Security's (MSS) Tianjin State Security Bureau and worked for the Huaying Haitai Science and Technology Development Company. menuPass has targeted healthcare, defense, aerospace, finance, maritime, biotechnology, energy, and government sectors globally, with an emphasis on Japanese organizations. In 2016 and 2017, the group is known to have targeted managed IT service providers (MSPs), manufacturing and mining companies, and a university.
G1021	Cinnamon Tempest Cinnamon Tempest is a China-based threat group that has been active since at least 2021 deploying multiple strains of ransomware based on the leaked Babuk source code. Cinnamon Tempest does not operate their ransomware on an affiliate model or purchase access but appears to act independently in all stages of the attack lifecycle. Based on victimology, the short lifespan of each ransomware variant, and use of malware attributed to government-sponsored threat groups, Cinnamon Tempest may be motivated by intellectual property theft or cyberespionage rather than financial gain.