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TSPY_ZBOT.DSA

April 09, 2013
 ALIASES:

VirTool:Win32/CeeInject (Microsoft); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Dropper.Generic7.BWRU (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This spyware 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:

650,024 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

09 Apr 2013

Arrival Details

This spyware 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 spyware creates the following folders:

  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Profile%\Application Data\{0F4F0AA9-8E9B-471E-9844-D0F9C5FBADC0}
  • %User Temp%\nsz4.tmp
  • %User Temp%\nsh6.tmp
  • %Program Files%\Yahoo!

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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 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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This spyware modifies the following file(s):

  • %User Profile%\Application Data\Microsoft

(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.)

It deletes the following files:

  • %User Temp%\nsa1.tmp
  • %User Temp%\nsz3.tmp
  • %User Temp%\nsz4.tmp
  • %User Temp%\nsr5.tmp
  • %User Temp%\nsh6.tmp

(Note: %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.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Yahoo\
SuiteInstaller

HKEY_CURRENT_USER\Software\Yahoo\
pager

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Yahoo\
SuiteInstaller
Full = "ezA1OEQ3OTE2LTQwQ0EtNDYwMy05ODQzLTVENkQwRTQ3NTI3Rn0="

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyHttp1.1 = "1"

HKEY_CURRENT_USER\Software\Yahoo\
pager
MD_ID_VALUE = "ID=ezA1OEQ3OTE2LTQwQ0EtNDYwMy05ODQzLTVENkQwRTQ3NTI3Rn0="

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}o.com/?ilc=8"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

Dropping Routine

This spyware drops the following files:

  • %User Temp%\nsa2.tmp
  • %User Temp%\Vorasasahew.dll
  • %User Temp%\gotovigela.Wab
  • %User Temp%\mufeqitetow.dll
  • %User Temp%\femogozika.dll
  • %User Temp%\jozukeyigoca.dll
  • %User Temp%\henoyuhuqiwo.exe
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • %User Temp%\Y!.exe
  • %User Temp%\nsz4.tmp\System.dll
  • %User Temp%\nsz4.tmp\bootstrap.ini
  • %User Temp%\nsz4.tmp\Base64.dll
  • %User Temp%\nsz4.tmp\ymsgr_suite_setup.exe
  • %User Temp%\nsz4.tmp\YExecShell.dll
  • %User Temp%\nsh6.tmp\System.dll
  • %User Temp%\nsh6.tmp\InetLoad_vms.dll
  • %User Temp%\nsh6.tmp\ymsgr11_us.ini
  • %User Temp%\nsh6.tmp\nsa7.tmp.htm
  • %User Temp%\nsh6.tmp\nsy8.tmp.htm
  • %User Temp%\nsh6.tmp\s1.bmp
  • %User Temp%\nsh6.tmp\s2.bmp
  • %User Temp%\nsh6.tmp\s3.bmp
  • %User Temp%\nsh6.tmp\s4.bmp
  • %User Temp%\nsh6.tmp\s5.bmp
  • %User Temp%\nsh6.tmp\ywiseextU.dll
  • %User Temp%\nsh6.tmp\eula.rtf
  • %User Temp%\nsh6.tmp\finish.ini
  • %User Temp%\nsh6.tmp\legal.ini
  • %User Temp%\nsh6.tmp\review.ini
  • %User Temp%\nsh6.tmp\software.ini
  • %User Temp%\nsh6.tmp\welcome.ini
  • %User Temp%\nsh6.tmp\modern-header.bmp
  • %User Temp%\nsh6.tmp\InstallOptions.dll
  • %User Temp%\nsh6.tmp\bb.html
  • %User Temp%\nsh6.tmp\stack.dll
  • %User Temp%\nsh6.tmp\ymsgr_inst.exe

(Note: %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 spyware connects to the following possibly malicious URL:

  • http://rd.{BLOCKED}re.yahoo.com/msgr/11/ini/ymsgr11_us.ini
  • http://rd.{BLOCKED}re.yahoo.com/ycontent/stats.php?{random characters}
  • http://rd.{BLOCKED}re.yahoo.com/appusage.asp
  • http://c-ymsgr11500228usexe.{BLOCKED}senger.http.atlas.cdn.yimg.com/ymessenger/dl/msgr11/ymsgr1150_0228_us.exe?m=application%2foctet-stream

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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\Yahoo
    • SuiteInstaller
  • In HKEY_CURRENT_USER\Software\Yahoo
    • pager

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\Yahoo\SuiteInstaller
    • Full = "ezA1OEQ3OTE2LTQwQ0EtNDYwMy05ODQzLTVENkQwRTQ3NTI3Rn0="
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyHttp1.1 = "1"
  • In HKEY_CURRENT_USER\Software\Yahoo\pager
    • MD_ID_VALUE = "ID=ezA1OEQ3OTE2LTQwQ0EtNDYwMy05ODQzLTVENkQwRTQ3NTI3Rn0="

Step 4

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}o.com/?ilc=8"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}o.com/?ilc=8"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Default_Page_URL = "http://www.{BLOCKED}o.com/?ilc=8"
      To: Default_Page_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""

Step 5

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.
  • %User Temp%\nsa2.tmp
  • %User Temp%\Vorasasahew.dll
  • %User Temp%\gotovigela.Wab
  • %User Temp%\mufeqitetow.dll
  • %User Temp%\femogozika.dll
  • %User Temp%\jozukeyigoca.dll
  • %User Temp%\henoyuhuqiwo.exe
  • %User Profile%\Microsoft\Crypto
  • %User Profile%\Crypto\RSA
  • %User Profile%\RSA\S-1-5-21-4025279379-4087772427-2915903831-500
  • %User Temp%\Y!.exe
  • %User Temp%\nsz4.tmp\System.dll
  • %User Temp%\nsz4.tmp\bootstrap.ini
  • %User Temp%\nsz4.tmp\Base64.dll
  • %User Temp%\nsz4.tmp\ymsgr_suite_setup.exe
  • %User Temp%\nsz4.tmp\YExecShell.dll
  • %User Temp%\nsh6.tmp\System.dll
  • %User Temp%\nsh6.tmp\InetLoad_vms.dll
  • %User Temp%\nsh6.tmp\ymsgr11_us.ini
  • %User Temp%\nsh6.tmp\nsa7.tmp.htm
  • %User Temp%\nsh6.tmp\nsy8.tmp.htm
  • %User Temp%\nsh6.tmp\s1.bmp
  • %User Temp%\nsh6.tmp\s2.bmp
  • %User Temp%\nsh6.tmp\s3.bmp
  • %User Temp%\nsh6.tmp\s4.bmp
  • %User Temp%\nsh6.tmp\s5.bmp
  • %User Temp%\nsh6.tmp\ywiseextU.dll
  • %User Temp%\nsh6.tmp\eula.rtf
  • %User Temp%\nsh6.tmp\finish.ini
  • %User Temp%\nsh6.tmp\legal.ini
  • %User Temp%\nsh6.tmp\review.ini
  • %User Temp%\nsh6.tmp\software.ini
  • %User Temp%\nsh6.tmp\welcome.ini
  • %User Temp%\nsh6.tmp\modern-header.bmp
  • %User Temp%\nsh6.tmp\InstallOptions.dll
  • %User Temp%\nsh6.tmp\bb.html
  • %User Temp%\nsh6.tmp\stack.dll
  • %User Temp%\nsh6.tmp\ymsgr_inst.exe

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.
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\ADMINI~1
  • %User Profile%\LOCALS~1
  • %User Profile%\Application Data\{0F4F0AA9-8E9B-471E-9844-D0F9C5FBADC0}
  • %User Temp%\nsz4.tmp
  • %User Temp%\nsh6.tmp
  • %Program Files%\Yahoo!

Step 7

Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.DSA. 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 8

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %User Profile%\Application Data\Microsoft

Step 9

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 Temp%\nsa1.tmp
  • %User Temp%\nsz3.tmp
  • %User Temp%\nsz4.tmp
  • %User Temp%\nsr5.tmp
  • %User Temp%\nsh6.tmp


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