Analysis by: Maria Emreen Viray
ALIASES:

Backdoor:Linux/RotaJakiro.A!MTB (MICROSOFT)

 PLATFORM:

Linux

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 133,632 bytes
File Type: None
Memory Resident: Yes
Initial Samples Received Date: 18 May 2021
Payload: Connects to URLs/IPs, Drops files

Arrival Details

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Backdoor drops the following copies of itself into the affected system:

  • For non-root user:
    • $HOME/.gvfsd/.profile/gvfsd-helper
    • $HOME/.dbus/sessions/session-dbus
  • For root user: (one of the following):
    • /usr/lib/systemd/systemd-daemon
    • /bin/systemd/systemd-daemon

It adds the following processes:

  • For non-root user:
    • $HOME/.gvfsd/.profile/gvfsd-helper
    • $HOME/.dbus/sessions/session-dbus
  • For root user:
    • (systemctl enable systemd-agent.service) >/dev/null 2>&1
    • (systemctl start systemd-agent.service) >/dev/null 2>&1

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Terminate process
  • Set timeout for connection to C2 server
  • Get device information and send to server
  • Create a file
  • Query file status
  • Deletes a file
  • Run a plugin

It connects to the following websites to send and receive information:

  • status.{BLOCKED}eover.net:443
  • blog.{BLOCKED}cts.com:443
  • news.{BLOCKED}or.net:443
  • cdn.{BLOCKED}-codes.net:443

Other Details

This Backdoor does the following:

  • It creates/modifies the following files to establish persistence:
    • For non-root user:
      • creates the following autostart script:
        • $HOME/.config/autostart/gnomehelper.desktop
          contains the following contents:
          • [Desktop Entry]
          • Type=Application
          • Exec=$HOME/.gvfsd/.profile/gvfsd-helper
          • Name=GNOME Helper
      • modifies the following file:
        • ~/.bashrc
          adds the following contents:
          • if [ -d ${HOME} ]; then
          • ${HOME}/.gvfsd/.profile/gvfsd-helper
          • fi
    • For root user:
      • creates the following autostart script:
        • /lib/systemd/system/systemd-agent.service
          contains the following contents:
          • [Unit]
          • Description=System Daemon
          • Wants=network-online.target
          • After=network-online.target
          • [Service]
          • ExecStart=/usr/lib/systemd/systemd-daemon
          • Restart=always
          • [Install]
          • WantedBy=multi-user.target

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.800.07
FIRST VSAPI PATTERN DATE: 24 Jun 2021
VSAPI OPR PATTERN File: 16.801.00
VSAPI OPR PATTERN Date: 25 Jun 2021

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Linux.ROTAJAKIRO.A. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:


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