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BKDR_FAKEMS.TRWS

February 10, 2015
 Analysis by: Rika Joi Gregorio
 ALIASES:

MSIL/Injector.GFB!tr(Fortinet), Trojan-PSW.Win32.Fareit(Ikarus), a variant of MSIL/Injector.GFB trojan(Eset)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • 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 executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

1,823,744 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Feb 2015

Payload:

Connects to URLs/IPs

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 copies of itself into the affected system and executes them:

  • %Application Data%\WindowsUpdate.exe
  • %Application Data%\Microsoft\atiesrx.exe
  • %User Profile%\Templates\takshost.exe
  • %Application Data%\Windows Update.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It drops the following files:

  • %Application Data%\pid.txt
  • %Application Data%\pidloc.txt
  • %User Temp%\SysInfo.txt

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %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 and executes the following files:

  • %Application Data%\Microsoft\IpOverUsbSvrc.exe - detected as TROJ_EYELOAD.A

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

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\Run
Windows Update = "%Application Data%\WindowsUpdate.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\atiesrx

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\atiesrx\
DEBUG

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\takshost

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\takshost\
DEBUG

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\Windows Update

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\Windows Update\
DEBUG

HKEY_LOCare\Microsoft\ESENT\
Process\{malwAL_MACHINE\Software file name}

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\{malware file name}\
DEBUG

It adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\atiesrx\
DEBUG
Trace Level = ""

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\{malware file name}\
DEBUG
Trace Level = ""

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\takshost\
DEBUG
Trace Level = ""

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\Windows Update\
DEBUG
Trace Level = ""

Backdoor Routine

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

  • Get clipboard data
  • Login credentials on web browsers and email servers
  • Visit/Block Website
  • Download file
  • Activate keylogging

Information Theft

This backdoor gathers the following data:

  • Browser cookies
  • POP3, IMAP, HTTPMail, SMTP, FTP, NNTP Passwords
  • System information

It attempts to steal stored email credentials from the following:

  • Eudora
  • Outlook Express
  • IncrediMail
  • Group mail Free
  • MS Outlook
  • Gmail
  • Hotmail/MSN
  • Yahoo! Mail
  • Netscape Mail
  • Thunderbird
  • Google Desktop
  • Windows Mail
  • Windows Live Mail

It attempts to get stored information such as user names, passwords, and hostnames from the following browsers:

  • Safari
  • Internet Explorer
  • Mozilla Firefox
  • Google Chrome
  • Opera
  • Sea Monkey
  • Thunderbird
  • Netscape

Stolen Information

This backdoor sends the data it gathers to the following email addresses via SMTP:

  • {BLOCKED}n@{BLOCKED}a.org.ph

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • www.msn.com

It connects to the following URL(s) to get the affected system's IP address:

  • http://whatismyipaddress.com

NOTES:
This malware opens www.msn.com using your default browser.

  SOLUTION

Minimum Scan Engine:

9.700

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

Remove malware/grayware files dropped/downloaded by BKDR_FAKEMS.TRWS. (Note: Please skip this step if the threats listed below have already been removed.)

    • TROJ_EYELOAD.A

Step 4

Restart in Safe Mode

[ Learn More ]

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.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\ESENT\Process
    • atiesrx
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\ESENT\Process
    • {malware file name}
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\ESENT\Process
    • takshost
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\ESENT\Process
    • Windows Update

Step 6

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\Run
    • Windows Update = "%Application Data%\WindowsUpdate.exe"

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.
  • %Application Data%\pid.txt
  • %Application Data%\pidloc.txt
  • %User Temp%\SysInfo.txt

Step 8

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