3CX voice and video conferencing software victim of a supply chain attack

Popular voice and video conferencing software 3CX was the victim of a supply chain attack, SentinelOne researchers reported.

As of Mar 22, 2023, SentinelOne observed a spike in behavioral detections of the 3CXDesktopApp, which is a popular voice and video conferencing software product.

The products from multiple cybersecurity vendors started detecting the popular software as malware suggesting that the company has suffered a supply chain attack.

SentinelOne is tracking the malicious activity as SmoothOperator, the company speculates that the threat actor behind the attack has set up its infrastructure starting as early as February 2022.

The company started distributing digitally signed Trojanized installers to its customers

“The trojanized 3CXDesktopApp is the first stage in a multi-stage attack chain that pulls ICO files appended with base64 data from Github and ultimately leads to a 3rd stage infostealer DLL still being analyzed as of the time of writing.” reads the analysis published by SentinelOne.

“At this time, we cannot confirm that the Mac installer is similarly trojanized. Our ongoing investigation includes additional applications like the Chrome extension that could also be used to stage attacks.”

The impact of the attack could be devastating because the company claims that 3CX has 600,000 customer companies with 12 million daily users. The software is used by organizations in almost every industry, including automotive, food & beverage, hospitality, Managed Information Technology Service Provider (MSP), and manufacturing.

3CX confirmed that the problem only affects the Windows Electron client for customers running update 7, it is working on an update to the DesktopApp. The company recommends uninstalling the app and then installing it again.

“Unfortunately the rumors are true. Please uninstall the client. And we will have a new one in the next few hours via updates. The updating probably wont work because Windows Defender will flag it.” explained 3CX’s CEO Nick Galea. “Unfortunately this happened because of an upstream library we use became infected.”

The trojanized 3CXDesktopApp is the first stage in a multi-stage attack chain, the installers retrieve ICO files appended with base64 data from Github and ultimately leading to the deployment of 3rd stage information stealer. The info stealer collects system information and gathers browser information from Chrome, Edge, Brave, and Firefox browsers. The malware can gather querying browsing history and data from the Places table for Firefox-based browsers and the History table for Chrome-based browsers.

The popular researcher Patrick Wardle analyzed the macOS version of the installer and confirmed it is a trojanized version using a valid signature. The researchers discovered that the malicious libffmpeg.dylib downloads a second-state malware from a remote server and executes a file named UpdateAgent.

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Pierluigi Paganini

(SecurityAffairs – hacking, 3CX)

Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.