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ELF_BEIKDOR.W

June 03, 2015
 Analysis by: Miguel Carlo Ang
 ALIASES:

HEUR:Backdoor.Linux.Ganiw.a(Kaspersky);Linux/Setag.B(ESET-NOD32);Linux/Backdoor.J(AVG)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

716,936 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

16 May 2015

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 files:

  • /tmp/notify.file
  • /tmp/gates.lock
  • /usr/bin/bsd-port/getty.lock
  • /tmp/notify.file
  • /usr/bin/bsd-port/udevd.lock
  • /usr/bin/dpkgd/{module path}
  • /tmp/moni.lock
  • /tmp/notify.file

NOTES:

This malware adds the following script in /etc/rc{1-5}.d/ and /etc/init.d/ to automatically execute itself when the system starts up:

/etc/rc1.d/SS97DbSecuritySpt
/etc/rc2.d/SS97DbSecuritySpt
/etc/rc3.d/SS97DbSecuritySpt
/etc/rc4.d/SS97DbSecuritySpt
/etc/rc5.d/SS97DbSecuritySpt
/etc/rc1.d/S99selinux
/etc/rc2.d/S99selinux
/etc/rc3.d/S99selinux
/etc/rc4.d/S99selinux
/etc/rc5.d/S99selinux
/etc/init.d/DbSecuritySpt
/etc/init.d/selinux

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.672.04

FIRST VSAPI PATTERN DATE:

16 May 2015

VSAPI OPR PATTERN File:

11.673.00

VSAPI OPR PATTERN Date:

17 May 2015

NOTES:

Step 1

Scan your computer with your Trend Micro product and note files detected as ELF_BEIKDOR.W.

Step 2

Terminate the malware process.

  1. Open the Terminal. Access Applications>Accessories>Terminal or press CTRL + ALT then T.
  2. Type the following in the terminal:
    ps –A
  3. Look for the detected files and take note of their PIDs. Enter the following commands for each PIDs:
    kill {PID}

Step 3

Remove autostart scripts. In the same Terminal, type the following command:

sudo rm -f /etc/rc1.d/SS97DbSecuritySpt
sudo rm -f /etc/rc2.d/SS97DbSecuritySpt
sudo rm -f /etc/rc3.d/SS97DbSecuritySpt
sudo rm -f /etc/rc4.d/SS97DbSecuritySpt
sudo rm -f /etc/rc5.d/SS97DbSecuritySpt
sudo rm -f /etc/init.d/DbSecuritySpt
sudo rm -f /etc/rc1.d/S99selinux
sudo rm -f /etc/rc2.d/S99selinux
sudo rm -f /etc/rc3.d/S99selinux
sudo rm -f /etc/rc4.d/S99selinux
sudo rm -f /etc/rc5.d/S99selinux
sudo rm -f /etc/init.d/selinux

Step 4

Remove dropped files. In the same Terminal, type the following command:

sudo rm -f /tmp/notify.file
sudo rm -f /tmp/gates.lock
sudo rm -f /usr/bin/bsd-port/getty.lock
sudo rm -f /usr/bin/bsd-port/udevd.lock
sudo rm -f /usr/bin/dpkgd/{module path}
sudo rm -f /tmp/moni.lock
sudo rm -f /tmp/notify.file

Step 5

Scan your computer with your Trend Micro product to delete files detected as ELF_BEIKDOR.W. 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.


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