Silex IoT Worm

Silex is a newly observed worm targeting unsecured Internet-of-Things (IoT) devices.

Threat ID:: CC-3120
Category:: Worm
Threat Severity:: Low
Threat Vector:: Exploit, Insecure network
Published:: 27 June 2019 12:00 AM

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

Summary

Silex is a newly observed worm targeting unsecured Internet-of-Things (IoT) devices.

Affected platforms

The following platforms are known to be affected:

Linux

IoT Devices

Linux web servers

Threat details

It's author has stated that it is based on the older Brickerbot permanent denial-of-service (PDoS) malware and that it is intended to prevent said devices being enrolled in botnets such as Mirai.

Devices are compromised using default Telnet (port 23) credentials. Once it has gained access, Silex will add iptables entries to drop all incoming or outgoing connections before writing random data to any storage partitions it discovers. It will then halt or reboot the device, resulting in a boot failure.

Remediation steps

Type	Step
	Telnet is a known insecure protocol. Organisations should consider closing port 23 and use more secure protocols such as Secure Shell. Additionally, 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. 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

Telnet is a known insecure protocol. Organisations should consider closing port 23 and use more secure protocols such as Secure Shell.

Additionally, 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.
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: 11 January 2022 9:48 am