Analysis by: RonJay Kristoffer Caragay
ALIASES:

Trojan-Dropper.Win32.Dorifel.amzn (Kaspersky); a variant of Win32/Injector.BOVT trojana variant of Win32/Injector.BOVT trojan (ESET-NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 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 executes commands from a remote malicious user, effectively compromising the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 188,416 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Nov 2014
Payload: Steals information, 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 and executes the following files:

  • %User Temp%\{random number}.bat ← used to delete itself; deleted after execution
  • %User Profile%\{random filename}.exe ← detected as Mal_BigTof

(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.. %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 adds the following processes:

  • svchost.exe

It injects codes into the following process(es):

  • created svchost.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\Run
MSConfig = "%User Profile%\{random filename}.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
DeviceControl
DevData0 = "{hex values}" ← used to save its config data

HKEY_CURRENT_USER\Software\Microsoft\
DeviceControl
DevData1 = "{hex values}" ← used to save its config data

HKEY_CURRENT_USER\Software\Microsoft\
DeviceControl
DevData2 = "{hex values}" ← used to save its config data

HKEY_CURRENT_USER\Software\WinRAR
HWID = "{hex values}"

Backdoor Routine

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

  • download spam template (urls, name, subject)
  • send spam mails to the following mail servers:
    • mail.ru
    • google.com
    • yahoo.com
    • hotmail.com
    • aol.com
    • protection.outlook.com
  • download and execute either of the following plugins:
    • plg_antibot
    • plg_ddos
    • plg_locs
    • plg_miner
    • plg_protect
    • plg_proxy
    • plg_smtp
    • plg_sniff
    • plg_spread1
    • plg_spread2
    • plg_sys
    • plg_text
    • plg_webb
    • plg_webm
  • gathered and used email credentials from the following browsers, FTPs and email clients in sending messages

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

  • {BLOCKED}bgddtyh.biz
  • {BLOCKED}hbyrukl.ch
  • {BLOCKED}.{BLOCKED}.193.238
  • {BLOCKED}.{BLOCKED}.146.217.143
  • {BLOCKED}.{BLOCKED}.113.149
  • {BLOCKED}.{BLOCKED}.132.183
  • {BLOCKED}.{BLOCKED}0.208
  • {BLOCKED}.{BLOCKED}.107.90
  • {BLOCKED}.{BLOCKED}.82.36
  • {BLOCKED}.{BLOCKED}.7.42
  • {BLOCKED}.{BLOCKED}.101.121

Information Theft

This backdoor attempts to steal stored account information used in the following installed File Transfer Protocol (FTP) clients or file manager software:

  • 32BitFtp
  • 3D-FTP
  • AceBIT
  • BitKinex
  • BlazeFtp
  • Bullet Proof FTP
  • CoffeeCup
  • Cryer WebSitePublisher
  • Cyberduck
  • Far Manager\Far2\Far
  • FastTrack
  • FileZilla Client
  • FlashFXP 3
  • FlashFXP 4
  • FlashPeak BlazeFtp
  • FreshFTP
  • Frigate3
  • FTP Commander
  • FTP CONTROL
  • FTP Explorer
  • FTP Navigator
  • FTP Now
  • FTP++
  • FTPClient
  • FTPCON
  • FTPGetter
  • FTPInfo
  • FTPRush
  • FTPVoyager
  • FTPWare COREFTP
  • Ghisler Total Commander
  • Ghisler Windows Commander
  • Global Downloader
  • GlobalSCAPE CuteFTP
  • GlobalSCAPE CuteFTP 6 Home
  • GlobalSCAPE CuteFTP 6 Professional
  • GlobalSCAPE CuteFTP 7 Home
  • GlobalSCAPE CuteFTP 7 Professional
  • GlobalSCAPE CuteFTP 8 Home
  • GlobalSCAPE CuteFTP 8 Professional
  • GlobalSCAPE CuteFTP Lite
  • GlobalSCAPE CuteFTP Pro
  • GoFTP
  • GPSoftware Directory Opus
  • INSoftware NovaFTP
  • Ipswitch WS_FTP
  • LeapWare LeapFTP
  • LeechFTP
  • LinasFTP
  • Martin Prikryl WinSCP
  • MAS-Soft FTPInfo
  • My FTP
  • NCH Software ClassicFTP
  • NCH Software Fling
  • NetDrive
  • NetSarang
  • NexusFile
  • Nico Mak Computing WinZip FTP
  • Notepad++\NppFTP
  • RhinoSoft
  • Robo-FTP 3.7
  • SimonTatham PuTTY
  • SiteDesigner
  • SmartFTP
  • SoftX
  • Sota FFFTP
  • Staff-FTP
  • TurboFTP
  • UltraFXP
  • VanDyke SecureFX
  • Visicom Media
  • WebDrive
  • WinFTP

It attempts to steal stored email credentials from the following:

  • RimArts
  • Microsoft Outlook
  • Pocomail
  • IncrediMail
  • The Bat! by RITLabs.
  • Windows Live Mail
  • Windows Mail

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

  • Bromium
  • ChromePlus
  • Chromium
  • Comodo
  • Epic
  • FastStone Browser
  • Google Chrome
  • K-Meleon
  • Microsoft Internet Explorer
  • Mozilla Firefox
  • Mozilla SeaMonkey
  • Mozilla Thunderbird
  • Nicrome
  • Opera Software
  • RockMelt
  • Yandex

Other Details

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

  • microsoft.com
  • yahoo.com
  • google.com
  • mail.ru

It deletes itself after execution.

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.268.06
FIRST VSAPI PATTERN DATE: 10 Nov 2014
VSAPI OPR PATTERN File: 11.269.00
VSAPI OPR PATTERN Date: 10 Nov 2014

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_TOFSEE.YFY. (Note: Please skip this step if the threats listed below have already been removed.)

    • MAL_BIGTOF

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

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
    • MSConfig = "%User Profile%\{random filename}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\DeviceControl
    • DevData0 = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\DeviceControl
    • DevData1 = "{hex values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\DeviceControl
    • DevData2 = "{hex values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • HWID = "{hex values}"

Step 6

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