Tuesday, 14 September 2021 10:37

Intezer trio find Linux re-implementation of Cobalt Strike beacon Featured

Intezer trio find Linux re-implementation of Cobalt Strike beacon Image by OpenClipart-Vectors from Pixabay

Researchers from security firm Intezer Labs have found a re-implementation of the Cobalt Strike beacon, written from scratch, which works on both Windows and Linux systems.

The original Cobalt Strike is a penetration testing tool used by so-called red teams – and also by threat actors. There is an official version for Windows.

In a detailed blog post, Intezer's Avigayil Mechtinger, Ryan Robinson and Joakim Kennedy said they had found the software in August, with a fully undetected ELF implementation of Cobalt's Strike beacon.

It was christened Vermilion Strike and the trio said it was as yet undetectable by current scanning engines on the VirusTotal database.

Web Analytics
The sample that had been uploaded to VirusTotal had come from Malaysia. ELF, or the Executable and Linkable Format, is a common standard file format for executable files, object code, shared libraries, and core dumps on UNIX-like systems.

Last year, there were reports that the source code for Cobalt Strike had been leaked on Microsoft's software code repository, GitHub.

"The stealthy sample uses Cobalt Strike’s Command and Control (C2) protocol when communicating to the C2 server and has Remote Access capabilities such as uploading files, running shell commands and writing to files," Mechtinger, Robinson and Kennedy wrote.

The researchers said they had used telemetry from anti-virus vendor McAfee Enterprise ATR and concluded that this Linux sample had been active in the wild since August.

The targets were telecommunications companies, government agencies, IT companies, financial institutions and advisory companies around the world.

"Targeting has been limited in scope, suggesting that this malware is used in specific attacks rather than mass spreading," they added.

Later, after further analysis, Mechtinger, Robinson and Kennedy said they had found Windows samples that used the same C2 server, adding that the Linux and Windows variants has the same functionalities.

"The sophistication of this threat, its intent to conduct espionage, and the fact that the code hasn’t been seen before in other attacks, together with the fact that it targets specific entities in the wild, leads us to believe that this threat was developed by a skilled threat actor," they said.

Mechtinger, Robinson and Kennedy also provided a technical analysis of the Linux file and its links to Windows files, as also indicators of compromise.

Subscribe to ITWIRE UPDATE Newsletter here


The much awaited iTWire Shop is now open to our readers.

Visit the iTWire Shop, a leading destination for stylish accessories, gear & gadgets, lifestyle products and everyday portable office essentials, drones, zoom lenses for smartphones, software and online training.

PLUS Big Brands include: Apple, Lenovo, LG, Samsung, Sennheiser and many more.

Products available for any country.

We hope you enjoy and find value in the much anticipated iTWire Shop.



iTWire TV offers a unique value to the Tech Sector by providing a range of video interviews, news, views and reviews, and also provides the opportunity for vendors to promote your company and your marketing messages.

We work with you to develop the message and conduct the interview or product review in a safe and collaborative way. Unlike other Tech YouTube channels, we create a story around your message and post that on the homepage of ITWire, linking to your message.

In addition, your interview post message can be displayed in up to 7 different post displays on our the iTWire.com site to drive traffic and readers to your video content and downloads. This can be a significant Lead Generation opportunity for your business.

We also provide 3 videos in one recording/sitting if you require so that you have a series of videos to promote to your customers. Your sales team can add your emails to sales collateral and to the footer of their sales and marketing emails.

See the latest in Tech News, Views, Interviews, Reviews, Product Promos and Events. Plus funny videos from our readers and customers.


Sam Varghese

Sam Varghese has been writing for iTWire since 2006, a year after the site came into existence. For nearly a decade thereafter, he wrote mostly about free and open source software, based on his own use of this genre of software. Since May 2016, he has been writing across many areas of technology. He has been a journalist for nearly 40 years in India (Indian Express and Deccan Herald), the UAE (Khaleej Times) and Australia (Daily Commercial News (now defunct) and The Age). His personal blog is titled Irregular Expression.

Share News tips for the iTWire Journalists? Your tip will be anonymous




Guest Opinion

Guest Reviews

Guest Research

Guest Research & Case Studies

Channel News