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SLUB Backdoor

First observed in early 2019, SLUB is a modular C-- based backdoor that uses the GitHub Gist service and Slack messaging application as part of its command and control infrastructure.

Threat ID:
CC-2966
Category:
Backdoor
Threat Severity:
Medium
Threat Vector:
Exploit
Published:
8 March 2019 12:00 AM
Report a cyber attack: call 0300 303 5222 or email [email protected]

Summary

First observed in early 2019, SLUB is a modular C-- based backdoor that uses the GitHub Gist service and Slack messaging application as part of its command and control infrastructure.

Affected platforms

The following platforms are known to be affected:

Microsoft Windows

Microsoft Windows - All versions

Threat details

SLUB is delivered via watering hole attack using a multi-stage infection scheme. Malicious websites will drop and execute a DLL file on visiting devices by exploiting a VBScript vulnerability, CVE-2018-8174. This DLL file will first check for certain anti-virus processes on the system, terminating itself if any are present, before exploiting another vulnerability to escalate its privileges. It will then download and install the primary SLUB payload.

Once installed, SLUB will add new registry keys to maintain persistence before downloading its commands from a specific gist snippet. By default, SLUB has the following capabilities, although it appears to be able to load other modules for enhanced functionality:

  • List and terminate processes.
  • Download and execute commands.
  • Download, list, copy, transfer, delete or execute files.
  • Create and delete directories.
  • Read, write or query registry keys.
  • Take screenshots.

The results of any commands, including downloaded files or screenshots, are posted by SLUB to a private Slack workspace using a pair of embedded API tokens.

For further information:

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.
  • 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