BKDR_INJECTO.ERO

July 06, 2015
 Analysis by: David John Agni
 ALIASES:

Win32/Injector.CCFN (ESET-NOD32), W32/CCFN!tr (Fortinet)

 PLATFORM:

Windows

 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, 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 does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It gathers certain information on the affected computer.

It sends the information it gathers to remote users via HTTP Post.

It terminates itself if it detects it is being run in a virtual environment.

  TECHNICAL DETAILS

File Size:

123,923 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Jun 2015

Payload:

Drops 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.

Installation

This backdoor drops the following files:

  • %User Temp%\ch.gif
  • %User Temp%\channel.js
  • %User Temp%\lamtomeajnkea1321
  • %User Temp%\{random}\embryulcia.dll -> deleted afterwards detected as BKDR_INJECTO.ERO
  • %User Temp%\readme.txt

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It drops the following copies of itself into the affected system:

  • %AppDataLocal\LolClient\LolCache.exe

It adds the following processes:

  • svchost.exe
    or
  • explorer.exe

It creates the following folders:

  • %AppDataLocal\LolClient
  • %AppDataLocal\LolClient\mod

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • XNXGv3IzwCz
  • hOImBA7our6

It injects codes into the following process(es):

  • Added Process

It terminates itself if it finds the following processes in the affected system's memory:

  • ollydbg.exe
  • wireshark.exe
  • smsniff.exe

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
LeagueofLegendsCache = "%AppDataLocal%\LolClient\LolCache.exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
Load = "%AppDataLocal%\LolClient\LolCache.exe"

Other System Modifications

This backdoor adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\SOFTWARE\LeagueofLegendsCache
pcid = "{GUID}"

HKEY_CURRENT_USER\SOFTWARE\LeagueofLegendsCache
mpid = "{malware process ID}"

HKEY_CURRENT_USER\SOFTWARE\LeagueofLegendsCache
wpid = "{malware child process ID}"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate\
AU
NoAutoUpdate = "1"

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows NT\SystemRestore
DisableSR = "1"

It adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\SOFTWARE\LeagueofLegendsCache

HKEY_CURRENT_USER\SOFTWARE\LeagueofLegendsCache\
mod

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Download file
  • Execute file
  • Load module
  • Update itself
  • Uninstall itself
  • Connect to other URL
  • Terminate Itself

It connects to the following websites to send and receive information:

  • http://{BLOCKED}jala.website:1337/1337/access.php
  • http://{BLOCKED}nn.com:1337/1337/access.php

Download Routine

This backdoor saves the files it downloads using the following names:

  • %User Temp%\{random filename}

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Information Theft

This backdoor gathers the following information on the affected computer:

  • OS Version
  • OS Bit Version
  • If running as administrator

Drop Points

This backdoor sends the information it gathers to remote users via HTTP Post.

Other Details

This backdoor terminates itself if it detects it is being run in a virtual environment.

  SOLUTION

Minimum Scan Engine:

9.750

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
    • LeagueofLegendsCache = "%AppDataLocal%\LolClient\LolCache.exe"
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • Load = "%AppDataLocal%\LolClient\LolCache.exe"

Step 5

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CURRENT_USER\SOFTWARE
    • LeagueofLegendsCache

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %AppDataLocal\LolClient

Step 7

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\ch.gif
  • %User Temp%\channel.js
  • %User Temp%\lamtomeajnkea1321
  • %User Temp%\readme.txt
  • %User Temp%\{random}\embryulcia.dll

Step 8

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

Step 9

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU
    • From: NoAutoUpdate = "1"
      To: NoAutoUpdate = 0
  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\SystemRestore
    • From: DisableSR = "1"
      To: DisableSR = 0

Step 10

Scan your computer with your Trend Micro product to delete files detected as BKDR_INJECTO.ERO. 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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