HijackLoader, a modular malware loader first observed in 2023, has continued to evolve by incorporating sophisticated evasion and delivery techniques. This malware variant is now using PNG images as a conduit to deliver next-stage payloads such as Amadey and Racoon Stealer. The new functionalities include process creation, User Account Control (UAC) bypass, and the use of anti-hooking techniques like Heaven’s Gate, which allows it to operate more stealthily. Additionally, it employs dynamic API resolution and employs blacklisting methods to evade detection by security software, making it a potent threat in the cyber landscape.
The malware’s execution process begins with its first stage dynamically resolving APIs through the traversal of the Portable Executable (PE) header using the SDBM hashing algorithm. This is primarily to locate and utilize WinHTTP APIs to check for internet connectivity. Once connectivity is established, the loader uses a simple mathematical addition to decrypt the embedded shellcode, preparing the system for the subsequent execution stages. This initial phase is critical as it sets the stage for the deeper infiltration of the infected system.
In the second stage of its operation, HijackLoader checks for predefined conditions within the malware’s code. If certain conditions are met, it utilizes an embedded PNG file containing encrypted modules. If not, it downloads a PNG file, scanning for specific headers to locate the necessary modules. These encrypted modules within the PNG are then decrypted using a specific key and decompressed using LZNT1 compression technique. Subsequently, a designated DLL is loaded, and a specific module named “ti” is injected for execution, indicating a highly methodical and multi-layered attack strategy.
Researchers, particularly those from Zscaler, have analyzed HijackLoader samples to identify the malware distributed through its channels. The findings show that Amadey was the most prevalent payload, detected in 52.9% of instances, followed by information stealers like Lumma Stealer, Racoon Stealer v2, and Meta Stealer. These payloads are primarily aimed at stealing sensitive information such as passwords, crypto wallets, and browser data. Furthermore, Remcos, a Remote Access Trojan (RAT), was also identified among the payloads, providing backdoor access to the infected systems. This diverse array of distributed malware underlines the multifunctional capability of HijackLoader as a delivery platform for various cyber threats.
