Skidmap Linux Rootkit

Skidmap is a newly observed rootkit targeting Linux systems, primarily web servers, in order to enrol them into cryptocurrency mining botnets.

Threat ID:: CC-3187
Category:: Rootkit
Threat Severity:: Medium
Threat Vector:
Published:: 18 September 2019 12:00 AM

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

Summary

Skidmap is a newly observed rootkit targeting Linux systems, primarily web servers, in order to enrol them into cryptocurrency mining botnets.

Affected platforms

The following platforms are known to be affected:

Linux

Linux - All major distributions

Threat details

At the time of publication, it is unclear how Skidmap is initially delivered, although the nature of its targets suggests its operators are manually identifying systems, gaining access, and dropping a preliminary script. This script is then executed to create a cron job to download and install Skidmap's main binary. Skidmap will then attempt to disable any SELinux security policies before deploying a backdoor to allow its operators access to any users present on the affected system.

Once this is done, Skidmap will check if the installed operating systems is Debian- or CentOS/RHEL-based, before unpacking and installing an unnamed cryptocurrency miner. It will then make several system calls to hide its files, and disguise network and CPU statistics to prevent detection when mining.

Remediation steps

Type	Step
	To prevent and detect an 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. All day-to-day computer activities such as email and internet are performed using non-administrative accounts. Strong password policies are in place and password reuse is discouraged. 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 an 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.
All day-to-day computer activities such as email and internet are performed using non-administrative accounts.
Strong password policies are in place and password reuse is discouraged.
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 2:58 pm