Analysis by: Jeanne Jocson
ALIASES:

OSX.Backdoor.Quimitchin (Malwarebytes)

 PLATFORM:

Linux, MacOSX

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

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 connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

It steals certain information from the system and/or the user.

  TECHNICAL DETAILS

File Size: 82,947 bytes
File Type: Script
Memory Resident: Yes
Initial Samples Received Date: 19 Jan 2017
Payload: Steals information, Connects to URLs/IPs

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 and executes the following files:

  • /tmp/proxy←detected by Trend Micro as PERL_QUIMITCHIN.A
  • /tmp/cr←detected by Trend Micro as OSX_QUIMITCHIN.A
  • /tmp/client.class←detected by Trend Micro as JAVA_QUIMITCHIN.A

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • eidk.{BLOCKED}o.org

However, as of this writing, the said sites are inaccessible.

Information Theft

This backdoor steals the following information:

  • System's hostname
  • Local hostname
  • Username

Other Details

Based on analysis of the codes, it has the following capabilities:

  • take screenshots using "xwd" commang and save it to:
    • /tmp/scrn.png
  • get system's uptime

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.168.02
FIRST VSAPI PATTERN DATE: 19 Jan 2017
VSAPI OPR PATTERN File: 13.169.00
VSAPI OPR PATTERN Date: 20 Jan 2017

NOTES:

  1. Scan using Trend Micro product and take note of the folder where this malware is detected.
  2. Identify and terminate the malware process using the noted folder in the previous step:
    • Open the Terminal. Click on Applications>Utilities>Terminal or type Terminal in Spotlight.
    • Type the following in the terminal: ps –A
    • Look for the detected files and take note of their PIDs. If the detected files are not found to be running, please proceed to the next step.
    • In the same terminal, enter the following commands for each PIDs: kill {PID}
  3. Delete the malware files/components.
    • -In the same Terminal, type the following commands and press enter per line: sudo rm –R "/tmp/cr"
      sudo rm –R "/tmp/proxy"
      sudo rm –R "/tmp/client.class"
      sudo -s
      rm –R "/private/var/root/.JavaW"

      If the malware files/components are not found, please proceed to the next step.
  4. Scan your computer with your Trend Micro product to delete files detected as OSX_IWORM.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.


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