New Linux backdoor BPFDoor found on systems, method of access unknown

British security researcher Kevin Beaumont has listed details about a backdoor that is claimed to infect Linux systems, with the consulting firm PwC having documented it as well. Both claim the threat emanates from China.

Called BPFDoor, there is no indication from either PwC or Beaumont as to how the backdoor gains a foothold on any system.

Beaumont said it used a BPF packet filter and hence could do its job without opening any new network ports or firewall rules.

PwC Threat Intelligence mentioned BPFDoor in its threat report for 2021, calling the individual(s) behind it Red Menshen, and claiming it had been targeting telcos in the Middle East and Asia.

It “also identified that the threat actor sends commands to BPFDoor victims via virtual private servers hosted at a well-known provider, and that these VPSs, in turn, are administered via compromised routers based in Taiwan, which the threat actor uses as VPN tunnels “.

Beaumont said he had found BPFDoor installed in a number of organizations in 2021, in the US, South Korea, Hong Kong, Turkey, India, Vietnam and Myanmar. These included systems in government, postal, logistics and education institutions.

“Operators have access to a tool which allows communication to the implants, using a password, which allows features such as remotely executing commands. This works over internal and Internet networks,” he wrote.

“Because BPFDoor doesn’t open any inbound network ports, doesn’t use an outbound C2, and it renames its own process in Linux (so ps aux, for example, will show a friendly name) it is highly evasive.”

PwC mentioned that its research showed Red Menshen was mostly active “between Monday to Friday (with none observed on the weekends), with most communication taking place between 01:00 and 10:00 UTC. This pattern suggests a consistent 8 to 9-hour activity window for the threat actor, with realistic probability of it aligning to local working hours”.

Beaumont pointed out that each implant had its own hash, making detection by searching for hashes a waste of time.

He said another researcher, Florian Roth, had discovered source code for the BPFDoor controller on VirusTotal, a database of malware signatures owned by Google.


The past year has seen a meteoric rise in ransomware incidents worldwide.

Over the past 12 months, SonicWall Capture Labs threat researchers have diligently tracked the meteoric rise in cyberattacks, as well as trends and activity across all threat vectors, including:

Encrypted threats
IoT malware
Zero-day attacks and more

These exclusive findings are now available via the 2022 SonicWall Cyber ​​Threat Report, which ensures SMBs, government agencies, enterprises and other organizations have the actionable intelligence needed to combat the rising tide of cybercrime threat.

Click the button below to get the report.



It’s all about Webinars.

Marketing budgets are now focused on Webinars combined with Lead Generation.

If you wish to promote a Webinar we recommend at least a 3 to 4 week campaign prior to your event.

The iTWire campaign will include extensive adverts on our News Site and prominent Newsletter promotion and Promotional News & Editorial. Plus a video interview of the key speaker on iTWire TV which will be used in Promotional Posts on the iTWire Home Page.

Now we are coming out of Lockdown iTWire will be focused to assisting with your webinars and campaigns and assistance via part payments and extended terms, a Webinar Business Booster Pack and other supportive programs. We can also create your adverts and written content plus coordinate your video interview.

We look forward to discussing your campaign goals with you. Please click the button below.



Leave a Comment