ELF_KAITEN.A

September 29, 2014
 Analysis by: Christopher Daniel So
 ALIASES:

Backdoor:Linux/Tsunami.gen!A (Microsoft), Linux.Backdoor.Kaiten (Symantec), Linux/Tsunami-A (Sophos), Backdoor.Linux.Tsunami (Ikarus)

 PLATFORM:

Linux, UNIX

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet

This backdoor connects to Internet Relay Chat (IRC) servers. It joins an Internet Relay Chat (IRC) channel. It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

982,256 bytes

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

28 Sep 2014

Payload:

Connects to URLs/IPs

Arrival Details

This backdoor may be downloaded from the following remote sites:

  • http://{BLOCKED}host.us/bots/a

This malware arrives via the following means:

Backdoor Routine

This backdoor connects to any of the following Internet Relay Chat (IRC) servers:

  • linksys.{BLOCKED}shellz.net:25

It joins any of the following Internet Relay Chat (IRC) channels:

  • #shellshock

It executes the following commands from a remote malicious user:

  • Perform PUSH-ACK flood
  • Perform SYN flood
  • Perform UDP flood with spoofed source address
  • Perform UDP flood without spoofed source address
  • Change nickname
  • Change server
  • Get spoofed source addresses
  • Set spoofed address subnet mask
  • Disable client
  • Enable client
  • Terminate client
  • Download file
  • Stop all attacks
  • Send raw IRC command
  • Start remote shell

NOTES:

This backdoor changes its process name to apache2 and clears its command line. It creates and locks the file /tmp/.z to ensure that only one copy of itself is running.

The IRC nickname it uses is a randomly generated string.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.178.04

FIRST VSAPI PATTERN DATE:

28 Sep 2014

Restart in normal mode and scan your computer with your Trend Micro product for files detected as ELF_KAITEN.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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