Cybercriminals associated with the Vietnamese cybercrime ecosystem are exploiting social media platforms, including Meta-owned Facebook, as a means to distribute malware.
According to Mohammad Kazem Hassan Nejad, a researcher from WithSecure, malicious actors have been utilizing deceptive ads to target victims with various scams and malvertising schemes. This tactic has become even more lucrative with businesses increasingly using social media for advertising, providing attackers with a new type of attack vector – hijacking business accounts.
Over the past year, cyber attacks against Meta Business and Facebook accounts have gained popularity, primarily driven by activity clusters like Ducktail and NodeStealer, known for targeting businesses and individuals operating on Facebook.
Social engineering plays a crucial role in gaining unauthorized access to user accounts, with victims being approached through platforms such as Facebook, LinkedIn, WhatsApp, and freelance job portals like Upwork. Search engine poisoning is another method employed to promote fake software, including CapCut, Notepad++, OpenAI ChatGPT, Google Bard, and Meta Threads.
Common tactics among these cybercrime groups include the misuse of URL shorteners, the use of Telegram for command-and-control (C2), and legitimate cloud services like Trello, Discord, Dropbox, iCloud, OneDrive, and Mediafire to host malicious payloads.
Ducktail, for instance, employs lures related to branding and marketing projects to infiltrate individuals and businesses on Meta's Business platform. In recent attacks, job and recruitment-related themes have been used to activate infections.
Potential targets are directed to fraudulent job postings on platforms like Upwork and Freelancer through Facebook ads or LinkedIn InMail. These postings contain links to compromised job description files hosted on cloud storage providers, leading to the deployment of the Ducktail stealer malware.
The Ducktail malware is designed to steal saved session cookies from browsers, with specific code tailored to take over Facebook business accounts. These compromised accounts are sold on underground marketplaces, fetching prices ranging from $15 to $340.
Recent attack sequences observed between February and March 2023 involve the use of shortcut and PowerShell files to download and launch the final malware. The malware has evolved to harvest personal information from various platforms, including X (formerly Twitter), TikTok Business, and Google Ads. It also uses stolen Facebook session cookies to create fraudulent ads and gain elevated privileges.
One of the primary methods used to take over a victim's compromised account involves adding the attacker's email address, changing the password, and locking the victim out of their Facebook account.
The malware has incorporated new features, such as using RestartManager (RM) to kill processes that lock browser databases, a technique commonly found in ransomware. Additionally, the final payload is obfuscated using a loader to dynamically decrypt and execute it, making analysis and detection more challenging.
To hinder analysis efforts, the threat actors use uniquely generated assembly names and rely on SmartAssembly, bloating, and compression to obfuscate the malware.
Researchers from Zscaler also observed instances where the threat actors initiated contact using compromised LinkedIn accounts belonging to users in the digital marketing field, leveraging the authenticity of these accounts to aid in social engineering tactics. This highlights the worm-like propagation of Ducktail, where stolen LinkedIn credentials and cookies are used to log in to victims' accounts and expand their reach.
Ducktail is just one of many Vietnamese threat actors employing shared tools and tactics for fraudulent schemes. A Ducktail copycat known as Duckport, which emerged in late March 2023, engages in information stealing and Meta Business account hijacking. Notably, Duckport differs from Ducktail in terms of Telegram channels used for command and control, source code implementation, and distribution, making them distinct threats.
Duckport employs a unique technique of sending victims links to branded sites related to the impersonated brand or company, redirecting them to download malicious archives from file hosting services. Unlike Ducktail, Duckport replaces Telegram as a channel for passing commands to victims' machines and incorporates additional information stealing and account hijacking capabilities, along with taking screenshots and abusing online note-taking services as part of its command and control chain.
"The Vietnamese-centric element of these threats and high degree of overlaps in terms of capabilities, infrastructure, and victimology suggests active working relationships between various threat actors, shared tooling and TTPs across these threat groups, or a fractured and service-oriented Vietnamese cybercriminal ecosystem (akin to ransomware-as-a-service model) centered around social media platforms such as Facebook," WithSecure said.
