Winnti Linux Malware

Winnti Linux is an updated variant of the Winnti backdoor, created by the advanced persistent threat group of the same name.

Threat ID:: CC-3070
Category:: Backdoor
Threat Severity:: Low
Threat Vector:: Spear phishing
Published:: 23 May 2019 12:00 AM

Report a cyber attack: call 0300 303 5222 or email [email protected]

Summary

Winnti Linux is an updated variant of the Winnti backdoor, created by the advanced persistent threat group of the same name.

Affected platforms

The following platforms are known to be affected:

Linux

Linux - Most popular distributions

Threat details

First observed in 2015, it is believed to be shared among a small group of trusted threat actors for use in their own disparate campaigns.

At the time of publication, Winnti Linux has only been observed being delivered through spear-phishing campaigns

Winnti Linux's primary module, called libxselinux, is a lightly modified version of the open-source Azazel rootlet. Once installed, it will decrypt an embedded port configuration file before connecting to a command and control server using a variety of protocols (HTTP, ICMP, and custom TCP/UDP) and modifying commonly used functions to disguise its operations. By default Winnti Linux is able to exfiltrate folders and files, execute arbitrary code, escalate privileges, and perform lateral network movements. Some variants are able to create a SOCKS5 proxy on affected systems, although it is unclear if this is a core capability or added functionality.

Remediation steps

Type	Step
	To prevent and detect a trojan infection, ensure that: A robust program of education and awareness training is delivered to users to ensure they don’t open attachments or follow links within unsolicited emails. All operating systems, anti-virus and other security products are kept up-to-date. Regular anti-virus and security scans are performed on your organisation’s estate. All day-to-day computer activities such as email and internet are performed using non-administrative accounts. Strong password policies are in place. Network, proxy and firewall logs should be monitored for suspicious activity. User accounts accessed from affected devices should be reset on a clean computer. Your organisation adopts a holistic all-round approach to Cyber Security as advocated by the 10 Steps to Cyber Security.

Type

Step

To prevent and detect a trojan infection, ensure that:

A robust program of education and awareness training is delivered to users to ensure they don’t open attachments or follow links within unsolicited emails.
All operating systems, anti-virus and other security products are kept up-to-date.
Regular anti-virus and security scans are performed on your organisation’s estate.
All day-to-day computer activities such as email and internet are performed using non-administrative accounts.
Strong password policies are in place.
Network, proxy and firewall logs should be monitored for suspicious activity.
User accounts accessed from affected devices should be reset on a clean computer.
Your organisation adopts a holistic all-round approach to Cyber Security as advocated by the 10 Steps to Cyber Security.

Last edited: 14 February 2020 2:48 pm