New OpcJacker Malware Distributed via Fake VPN Malvertising

OpcJacker is a modular malware discovered in late 2022 that uses a custom VM-like configuration to conceal its logic and load additional payloads. It combines credential theft, clipboard hijacking for cryptocurrency, keylogging, screen capture, and remote-loader capabilities, delivered via fake VPN/malvertising campaigns and ISO/ZIP installers.
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Keypoints

  • OpcJacker has been distributed since the second half of 2022 and uses a custom file format that resembles VM code to define its behavior, making analysis harder.
  • Primary capabilities include keylogging, screenshots, browser data theft, and clipboard-based cryptocurrency address replacement (clipper).
  • The malware is loaded by patching a legitimate DLL within an installed app, then loading another malicious DLL that runs shellcode and OpcJacker from data-file chunks (loader/cryptor chain).
  • Delivery involves fake websites and malvertising, with Iran geotargeting; campaigns push fake crypto apps/VPN and deliver OpcJacker via archives (ISO/RAR/ZIP).
  • OpcJacker drops or downloads remote-access modules (NetSupport RAT or hvnc) and can load the Phobos Crypter/Phobos ransomware payloads.
  • The malware implements persistence (registry, startup, task scheduler) and includes a clipper, keylogger, and capabilities to load embedded RAT modules; it also enumerates cryptocurrency wallet extensions and browsers.

MITRE Techniques

  • [T1547.001] Registry Run Keys/Startup Folder – Uses startup registry keys to achieve persistence. Quote: “Used for persistence (registry; HKCU)”
  • [T1053.005] Scheduled Task – Uses the Windows Task Scheduler for persistence. Quote: “Used for persistence (task scheduler)”
  • [T1574.001] DLL Search Order Hijacking – Patches a legitimate DLL in an installed application to load a malicious DLL. Quote: “patching a legitimate DLL library within an installed application, which loads another malicious DLL library”
  • [T1027] Obfuscated/Compressed Files and Information – Configuration uses a custom VM-like bytecode to hide behavior. Quote: “The format resembles custom virtual machine code, where numeric hexadecimal identifiers … make the stealer run desired functions.”
  • [T1021.001] Remote Services: VNC – Embedded hvnc variant used as a remote access tool. Quote: “remote access tools — either the NetSupport RAT or a hidden virtual network computing (hVNC) variant.”
  • [T1105] Ingress Tool Transfer – Loader drops/downloads and runs additional modules (remote-Access tools). Quote: “the malware … drops (or downloads) and runs additional modules, which are remote access tools”
  • [T1056.001] Keylogging – The stealer includes a keylogger (as per handler functionality). Quote: “Starts keylogger”
  • [T1113] Screen Capture – The malware can take screenshots. Quote: “Writes to screenshots”
  • [T1115] Clipboard Data – Clipboard hijacking to replace cryptocurrency addresses. Quote: “monitors the clipboard for cryptocurrency addresses and replaces them with the attackers’ addresses”
  • [T1555.003] Credentials from Web Browsers – Steals data from browsers. Quote: “stealing sensitive data from browsers”

Indicators of Compromise

  • [File Name] context – RawDigger.exe, mdb.dll, librawf.dll, libpushpp.dll, TradingViewDesktop.zip (and 2 more files)
  • [Hash] context – 18DF68D1581C11130C139FA52ABB74DFD098A9AF698A250645D6A4A65EFCBF2D, 49A568F8AC11173E3A0D76CFF6BC1D4B9BDF2C35C6D8570177422F142DCFDBE3
  • [Archive] context – CLF_security.iso, TradingViewDesktop.zip, XDag.x64.rar (and 2 more archives)

Read more: https://www.trendmicro.com/en_us/research/23/c/new-opcjacker-malware-distributed-via-fake-vpn-malvertising.html