TROJ_DROPR.YJNA

August 07, 2015

ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft); RDN/Generic BackDoor (McAfee); Trojan.Dionisduke (Symantec); HEUR:Trojan.Win32.Generic (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Atros.CAFF (AVG)

PLATFORM:

Windows

OVERALL RISK RATING:

DAMAGE POTENTIAL:

DISTRIBUTION POTENTIAL:

REPORTED INFECTION:

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes

OVERVIEW

This Trojan 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:

456,334 bytes

File Type:

EXE

Memory Resident:

Initial Samples Received Date:

07 Aug 2015

Arrival Details

This Trojan 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 Trojan creates the following folders:

%System Root%\DOCUME~1
%System Root%\DOCUME~1\Wilbert
%User Profile%\LOCALS~1
%User Temp%\
%User Profile%\Network\Downloader

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.. %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.)

Other System Modifications

This Trojan deletes the following files:

%User Profile%\10.0\ReaderMessages-journal
%Application Data%\Adobe\Acrobat\10.0\SharedDataEvents-journal
.\adobe.exe
%User Temp%\1.vbs

(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 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 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_LOCAL_MACHINE\Software\Adobe\
Acrobat Reader\10.0\AdobeViewer

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS\CtlGuid

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\BITS

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"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
LogSessionName = "stdout"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
Active = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
ControlFlags = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS\CtlGuid
Guid = "4a8aaa94-cfc4-46a7-8e4e-17bc45608f0a"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS\CtlGuid
BitNames = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\BackupRestore\FilesNotToBackup
BITS_metadata = "%User Profile%\Downloader\*"

Dropping Routine

This Trojan drops the following files:

__tmp_rar_sfx_access_check_33843
adobe.exe
382210.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\XF3T3XB2
%User Temp%\Temporary Internet Files\Content.IE5\SDWJOTMP
%User Temp%\Temporary Internet Files\Content.IE5\8XAF0PA7
%User Temp%\Temporary Internet Files\Content.IE5\6PQ9ABCD
%User Temp%\Cookies
%User Temp%\History
%User Temp%\History\History.IE5
.\1.vbs
%User Temp%\ArmUI.ini

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

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

This report is generated via an automated analysis system.

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

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_LOCAL_MACHINE\Software\Adobe\Acrobat Reader\10.0
- AdobeViewer

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft
- BITS

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- CtlGuid

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
- BITS

To delete the registry key this malware/grayware created:

Open Registry Editor.
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Adobe Acrobat
Still in the left panel, locate and delete the key:
10.0
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Adobe Synchronizer
Still in the left panel, locate and delete the key:
10.0
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>System
Still in the left panel, locate and delete the key:
Acrobatbrokerserverdispatchercpp789
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0>Installer
Still in the left panel, locate and delete the key:
Migrated
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0
Still in the left panel, locate and delete the key:
Originals
Again Still in the left panel, locate and delete the key:
AVGeneral
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>Software>Adobe>Acrobat Reader>10.0
Still in the left panel, locate and delete the key:
AdobeViewer
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Tracing>Microsoft
Still in the left panel, locate and delete the key:
BITS
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Tracing>Microsoft>BITS
Still in the left panel, locate and delete the key:
CtlGuid
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion
Still in the left panel, locate and delete the key:
BITS
Close Registry Editor.

Step 3

Delete this registry value

[ Learn More ]

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"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- LogSessionName = "stdout"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- Active = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- ControlFlags = "1"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS\CtlGuid
- Guid = "4a8aaa94-cfc4-46a7-8e4e-17bc45608f0a"

In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS\CtlGuid
- BitNames = "{random characters}"

In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\BackupRestore\FilesNotToBackup
- BITS_metadata = "%User Profile%\Downloader\*"

To delete the registry value this malware/grayware created:

Open Registry Editor.
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower-left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0>Installer>Migrated
In the right panel, locate and delete the entry:
{AC76BA86-7AD7-1033-7B44-AA0000000001} = "1"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0>Originals
In the right panel, locate and delete the entry:
bDisplayedSplash = "1"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0>AVGeneral
In the right panel, locate and delete the entry:
bLastExitNormal = "0"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Adobe>Acrobat Reader>10.0>AdobeViewer
In the right panel, locate and delete the entry:
EULA = "1"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Adobe>Acrobat Reader>10.0>AdobeViewer
In the right panel, locate and delete the entry:
EULA = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Tracing>Microsoft>BITS
In the right panel, locate and delete the entry:
LogSessionName = "stdout"
Again In the right panel, locate and delete the entry:
Active = "1"
Again In the right panel, locate and delete the entry:
ControlFlags = "1"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Tracing>Microsoft>BITS>CtlGuid
In the right panel, locate and delete the entry:
Guid = "4a8aaa94-cfc4-46a7-8e4e-17bc45608f0a"
Again In the right panel, locate and delete the entry:
BitNames = "{random characters}"
In the left panel, double-click the following:
HKEY_LOCAL_MACHINE>SYSTEM>ControlSet001>Control>BackupRestore>FilesNotToBackup
In the right panel, locate and delete the entry:
BITS_metadata = "%User Profile%\Downloader\*"
Close Registry Editor.

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_33843
adobe.exe
382210.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\XF3T3XB2
%User Temp%\Temporary Internet Files\Content.IE5\SDWJOTMP
%User Temp%\Temporary Internet Files\Content.IE5\8XAF0PA7
%User Temp%\Temporary Internet Files\Content.IE5\6PQ9ABCD
%User Temp%\Cookies
%User Temp%\History
%User Temp%\History\History.IE5
.\1.vbs
%User Temp%\ArmUI.ini

To manually delete a malware/grayware file from an affected system:

• For Windows 2000, Windows XP, and Windows Server 2003:

Right-click Start then click Search....
In the File name* input box, type the following:
__tmp_rar_sfx_access_check_33843
adobe.exe
382210.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\XF3T3XB2
%User Temp%\Temporary Internet Files\Content.IE5\SDWJOTMP
%User Temp%\Temporary Internet Files\Content.IE5\8XAF0PA7
%User Temp%\Temporary Internet Files\Content.IE5\6PQ9ABCD
%User Temp%\Cookies
%User Temp%\History
%User Temp%\History\History.IE5
.\1.vbs
%User Temp%\ArmUI.ini
In the Look In drop-down list, select My Computer then press Enter.
Once located, select the file then press SHIFT+DELETE to delete it.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).

• For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen,then click File Explorer.
In the Search Computer/This PC input box, type:
__tmp_rar_sfx_access_check_33843
adobe.exe
382210.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\XF3T3XB2
%User Temp%\Temporary Internet Files\Content.IE5\SDWJOTMP
%User Temp%\Temporary Internet Files\Content.IE5\8XAF0PA7
%User Temp%\Temporary Internet Files\Content.IE5\6PQ9ABCD
%User Temp%\Cookies
%User Temp%\History
%User Temp%\History\History.IE5
.\1.vbs
%User Temp%\ArmUI.ini
Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.

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.

%System Root%\DOCUME~1
%System Root%\DOCUME~1\Wilbert
%User Profile%\LOCALS~1
%User Temp%\
%User Profile%\Network\Downloader

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPR.YJNA. 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
.\adobe.exe
%User Temp%\1.vbs

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TROJ_DROPR.YJNA

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