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BKDR_SHOTODOR.UU

September 08, 2014
 ALIASES:

RDN/Generic.dx!d2w (McAfee); Troj/Malit-EX, Mal/MalitRar-B (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Ransomer.DOR (AVG)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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.

  TECHNICAL DETAILS

File Size:

849,566 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 Sep 2014

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 creates the following folders:

  • \Documents and Settings
  • \Documents and Settings\Wilbert
  • \Documents and Settings\Wilbert\39a51qsvds25
  • %User Profile%\10.0\Forms

(Note: %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.)

Other System Modifications

This backdoor deletes the following files:

  • %User Profile%\10.0\ReaderMessages-journal
  • %Application Data%\Adobe\Acrobat\10.0\SharedDataEvents-journal

(Note: %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.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Adobe\
Adobe Acrobat\10.0

HKEY_CURRENT_USER\Software\Adobe\
Adobe Synchronizer\10.0

HKEY_LOCAL_MACHINE\System\Acrobatbrokerserverdispatchercpp789

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Installer\
Migrated

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Originals

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AVGeneral

HKEY_CURRENT_USER\Software\Adobe\
Adobe Synchronizer\10.0\Acrobat.com

HKEY_CURRENT_USER\Software\Adobe\
Adobe Synchronizer\10.0\Acrobat.com.v2

HKEY_CURRENT_USER\Software\Adobe\
Adobe Acrobat\10.0\DiskCabs

HKEY_LOCAL_MACHINE\Software\Adobe\
Acrobat Reader\10.0\AdobeViewer

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Installer\
Migrated
{AC76BA86-7AD7-1033-7B44-AA0000000001} = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\Originals
bDisplayedSplash = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AVGeneral
bLastExitNormal = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\
Acrobat Reader\10.0\AdobeViewer
EULA = "1"

HKEY_CURRENT_USER\Software\Adobe\
Acrobat Reader\10.0\AdobeViewer
EULA = "1"

Dropping Routine

This backdoor drops the following files:

  • __tmp_rar_sfx_access_check_51265
  • mudpxppg.KLV
  • gynhsepmul.exe
  • tdscz.GMH
  • ivpoqqjgp.UIG
  • Payment_Advice(2).pdf
  • %Application Data%\Adobe\Color\ACECache11.lst
  • %Application Data%\Adobe\Acrobat\10.0\UserCache.bin
  • %User Temp%\Temporary Internet Files
  • %User Temp%\Temporary Internet Files\Content.IE5
  • %User Temp%\Temporary Internet Files\Content.IE5\X92FS56J
  • %User Temp%\Temporary Internet Files\Content.IE5\KT4V0VK9
  • %User Temp%\Temporary Internet Files\Content.IE5\OP6VS5Q7
  • %User Temp%\Temporary Internet Files\Content.IE5\CHMF4HMB
  • %User Temp%\Cookies
  • %User Temp%\History
  • %User Temp%\History\History.IE5
  • %User Profile%\10.0\rdrmessage.zip
  • %User Profile%\10.0\Forms

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %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.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://acroipm.{BLOCKED}e.com/10/rdr/ENU/win/nooem/none/message.zip
  • {BLOCKED}0.1
  • {BLOCKED}.40.203

This report is generated via an automated analysis system.

  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

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_CURRENT_USER\Software\Adobe\Adobe Acrobat
    • 10.0
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Synchronizer
    • 10.0
  • In HKEY_LOCAL_MACHINE\System
    • Acrobatbrokerserverdispatchercpp789
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\Installer
    • Migrated
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0
    • Originals
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0
    • AVGeneral
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Synchronizer\10.0
    • Acrobat.com
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Synchronizer\10.0
    • Acrobat.com.v2
  • In HKEY_CURRENT_USER\Software\Adobe\Adobe Acrobat\10.0
    • DiskCabs
  • In HKEY_LOCAL_MACHINE\Software\Adobe\Acrobat Reader\10.0
    • AdobeViewer

Step 3

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\Adobe\Acrobat Reader\10.0\Installer\Migrated
    • {AC76BA86-7AD7-1033-7B44-AA0000000001} = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\Originals
    • bDisplayedSplash = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\AVGeneral
    • bLastExitNormal = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Acrobat Reader\10.0\AdobeViewer
    • EULA = "1"
  • In HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\AdobeViewer
    • EULA = "1"

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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.
  • __tmp_rar_sfx_access_check_51265
  • mudpxppg.KLV
  • gynhsepmul.exe
  • tdscz.GMH
  • ivpoqqjgp.UIG
  • Payment_Advice(2).pdf
  • %Application Data%\Adobe\Color\ACECache11.lst
  • %Application Data%\Adobe\Acrobat\10.0\UserCache.bin
  • %User Temp%\Temporary Internet Files
  • %User Temp%\Temporary Internet Files\Content.IE5
  • %User Temp%\Temporary Internet Files\Content.IE5\X92FS56J
  • %User Temp%\Temporary Internet Files\Content.IE5\KT4V0VK9
  • %User Temp%\Temporary Internet Files\Content.IE5\OP6VS5Q7
  • %User Temp%\Temporary Internet Files\Content.IE5\CHMF4HMB
  • %User Temp%\Cookies
  • %User Temp%\History
  • %User Temp%\History\History.IE5
  • %User Profile%\10.0\rdrmessage.zip
  • %User Profile%\10.0\Forms

Step 5

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.
  • \Documents and Settings
  • \Documents and Settings\Wilbert
  • \Documents and Settings\Wilbert\39a51qsvds25
  • %User Profile%\10.0\Forms

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_SHOTODOR.UU. 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 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Profile%\10.0\ReaderMessages-journal
  • %Application Data%\Adobe\Acrobat\10.0\SharedDataEvents-journal


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