Analysis by: Michael John Marcos
ALIASES:

BV:Xorddos-B [Trj] (Avast), Linux/Xorddos.A (ESET), Linux.Xorddos (Symantec)

 PLATFORM:

Mac OS X, Unix, Linux

 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: Downloaded from the Internet

This backdoor may be downloaded by other malware/grayware/spyware from remote sites.

It connects to a website to send and receive information.

  TECHNICAL DETAILS

File Size: 7,174 bytes
File Type: Script
Memory Resident: No
Initial Samples Received Date: 09 Jan 2015
Payload: Connects to URLs/IPs, Downloads files

Arrival Details

This backdoor may be downloaded by other malware/grayware/spyware from remote sites.

Backdoor Routine

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

  • http://{BLOCKED}.{BLOCKED}.21.81
  • http://{BLOCKED}.{BLOCKED}.9.226
  • http://{BLOCKED}.{BLOCKED}.9.225 (if 64-bit)
  • http://{BLOCKED}.{BLOCKED}.21.76 (if 64-bit)

It posts the following information to its command and control (C&C) server:

  • iid={random value}
  • username={hardcoded username}
  • password={hard coded password}
  • ip={BLOCKED}.{BLOCKED}.9.245:8001|{BLOCKED}.{BLOCKED}.141.50:8001|{BLOCKED}.{BLOCKED}.253.30:8001|ndns.{BLOCKED}1.org:8001|ndns.{BLOCKED}a.org:8001|ndns.{BLOCKED}ao.com:8001|ndns.{BLOCKED}a.com:8001
  • ver=3.8.0
  • kernel={kernel version}

Download Routine

This backdoor connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}.{BLOCKED}.21.82/upload/8001

NOTES:

This backdoor creates a /tmp/{random value} folder. It makes the following changes:

  • /usr/bin/wget (Writable and executable)
  • /bin/wget (Writable and executable)
  • /usr/bin/cut (Writable and executable)
  • /bin/cut (Writable and executable)

This backdoor selects the malicious URLs to communicate to based on the processor of the infected system.

  SOLUTION

Minimum Scan Engine: 9.700

Scan your computer with your Trend Micro product to delete files detected as UNIX_XORDDOS.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 this Knowledge Base page for more information.


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