Backdoor.Linux.YOWAI.A

January 24, 2019
 Analysis by: Warren Adam Sto. Tomas
 ALIASES:

ELF/Mirai.AE!tr (Fortinet)

 PLATFORM:

Linux

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 listens on port(s). It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

82800 bytes

File Type:

ELF

Memory Resident:

No

Initial Samples Received Date:

15 Jan 2019

Payload:

Downloads files, Spreads through vulnerabilities, Terminates processes

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.

Backdoor Routine

This Backdoor listens on the following port(s):

  • 6

It executes the following commands from a remote malicious user:

  • Download a file
  • Performs various DDOS attacks
  • Execute shell commands
  • Uses default or easy-to-guess usernames and passwords to login to other devices

Other Details

This Backdoor does the following:

  • It may spread to other devices by taking advantage of the following vulnerabilities:
  • It uses the following credentials to try to login to other devices:
    • OxhlwSG8
    • tlJwpbo6
    • S2fGqNFs
    • admin
    • daemon
    • 12345
    • support
    • 4321
    • default
    • vizxv
    • t0talc0ntr0l4!
    • synnet
    • root
  • It displays the strings below once executed in the command line:
    • Yowai: Raping you sorry
  • It is capable of terminating processes which satisfies any of the following conditions:
    • memory of the process contains strings related to the following botnets:
      • dvrhelper
      • mirai
      • light
      • apex
      • Tsunami
      • hoho
      • nikki
      • miori
      • hybrid
      • sora
      • yakuza
      • kalon
      • owari
      • gemini
      • lessie
      • senpai
      • apollo
      • storm
      • Voltage
      • horizon
      • meraki
      • ice
      • Cayosin
      • Mafia
      • Helios
      • Sentinel
      • Furasshu
      • love
      • oblivion
      • lzrd
      • yagi
      • dark
      • blade
      • messiah
      • qbot
      • modz
      • ethereal
      • unix
      • execution
      • galaxy
      • kwari
      • okane
      • osiris
      • naku
      • demon
      • sythe
      • xova
      • trinity
      • BUSHIDO
      • IZ1H9
      • daddyl33t
      • KOWAI-SAD
      • ggtr
      • QBotBladeSPOOKY
      • SO190Ij1X
      • hellsgate
      • sysupdater
      • Katrina32
  • The files downloaded are saved as:
    • /tmp/Yowai.mips (CVE-2014-8361)
    • /tmp/Yowai.mpsl (Linksys Remote Code Execution)
    • /tmp/gaf (CVE-2018-10561)
    • /tmp/Yowaib (ThinkPHP exploit)
  • Once a vulnerable device is exploited, it will download and execute a file in the device from the following websites:
    • http://{BLOCKED}.{BLOCKED}.25.221/bins/Yowai.mips (CVE-2014-8361)
    • http://{BLOCKED}.{BLOCKED}.25.221/bins/Yowai.mpsl (Linksys Remote Code Execution)
    • http://{BLOCKED}.{BLOCKED}.25.221/bin (CVE-2018-10561)
    • http://{BLOCKED}.{BLOCKED}.25.221/bins/Yowai.x86 (ThinkPHP exploit)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.768.02

FIRST VSAPI PATTERN DATE:

15 Jan 2019

VSAPI OPR PATTERN File:

14.769.00

VSAPI OPR PATTERN Date:

16 Jan 2019

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Linux.YOWAI.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 the following Trend Micro Support pages for more information:


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