Description

Fortinet FortiGuard Labs identified a recent surge in a new variant of the remote access trojan Bandook, actively disseminated through phishing attacks, targeting Windows machines. Discovered in October 2023, this malware variant arrives concealed within a PDF file, which contains a link to a password-protected .7z archive. Upon extraction using the password embedded in the PDF, the malware infiltrates by injecting its payload into msinfo32.exe, a legitimate Windows binary. Originally detected in 2007, Bandook is an adaptable off-the-shelf malware renowned for its multifaceted capabilities, allowing remote control over compromised systems. Earlier, in July 2021, ESET reported a cyber espionage campaign utilizing an enhanced Bandook variant to breach corporate networks, primarily targeting Spanish-speaking nations like Venezuela. The attack methodology commences with an injector component decrypting and loading the payload into msinfo32.exe. Subsequently, the malware establishes persistence on the infected host by manipulating the Windows Registry and connects with a command-and-control (C2) server for additional instructions and payloads. Pei Han Liao, the security researcher, categorized the malware's actions, including file and registry manipulation, information theft, downloads, executing files, invoking functions from the C2's DLLs, controlling the victim's computer, process termination, and self-removal of the malware. This sophisticated suite of functionalities underscores Bandook's evolving threat landscape, demanding heightened vigilance against its stealthy and extensive infiltration strategies.