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TSPY_ZBOT.KFA

October 09, 2012
 Analysis by: Roland Marco Dela Paz
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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.

It is injected into all running processes to remain memory resident.

It modifies the Internet Explorer Zone Settings.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

323,073 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Aug 2012

Payload:

Connects to URLs/IPs

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 drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\{random1}\{random}.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It drops the following files:

  • %User Profile%\Application Data\{random2}\{random}.{random}
  • %User Profile%\Application Data\Microsoft\Address Book\winxp.wab
  • %User Profile%\Application Data\Microsoft\Address Book\winxp.wab~

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %User Profile%\Application Data\{random1}
  • %User Profile%\Application Data\{random2}
  • %User Profile%\Application Data\Microsoft\Address Book

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It is injected into all running processes to remain memory resident.

Autostart Technique

This spyware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%User Profile%\Application Data\{random1}\{random}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random}

HKEY_CURRENT_USER\Software\Microsoft\
WAB

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\0
1609 = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1406 = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1609 = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\2
1609 = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1406 = "0"

(Note: The default value data of the said registry entry is "3".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1609 = "0"

(Note: The default value data of the said registry entry is "1".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1406 = "0"

(Note: The default value data of the said registry entry is "3".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1609 = "0"

(Note: The default value data of the said registry entry is "1".)

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port}:UDP = {port}:UDP:Enabled:UDP {port}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port}:TCP = {port}:TCP:Enabled:TCP {port}

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

Download Routine

This spyware connects to the following URL(s) to download its configuration file:

  • {BLOCKED}.{BLOCKED}.206.128

As of this writing, the said sites are inaccessible.

Other Details

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

  • bing.com
  • google.com

NOTES:

The configuration file may contain URLs where it downloads an updated copy of itself and where it sends its gathered information. It may also contain URLs of its target online banking and finance-related sites from where it steals the information.

It may also gather the following information from the affected system:

  • Data on Cookie files (URLs)
  • Email information stored in the user's Windows Address Book (WAB) file
  • Email-related information such as account names, email addresses, passwords, server data, and server port

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

*under processing

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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\Microsoft
    • WAB

Step 4

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
    • {GUID} = %User Profile%\Application Data\{random1}\{random}.exe
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • {port}:UDP = {port}:UDP:Enabled:UDP {port}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • {port}:TCP = {port}:TCP:Enabled:TCP {port}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = %Windows%\explorer.exe:*:Enabled:Windows Explorer

Step 5

Restore this modified registry value

[ 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\Windows\CurrentVersion\Internet Settings\Zones\0
    • From: 1609 = 0
      To: 1609 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • From: 1406 = 0
      To: 1406 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • From: 1609 = 0
      To: 1609 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\2
    • From: 1609 = 0
      To: 1609 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1406 = 0
      To: 1406 = 3
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1609 = 0
      To: 1609 = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
    • From: 1406 = 0
      To: 1406 = 3
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
    • From: 1609 = 0
      To: 1609 = 1

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.
  • %User Profile%\Application Data\{random1}
  • %User Profile%\Application Data\{random2}
  • %User Profile%\Application Data\Microsoft\Address Book

Step 7

Reset Internet security settings

[ Learn More ]

Step 8

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

NOTES:

The created registry key HKEY_CURRENT_USER\Software\Microsoft\{random} cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup if the users have one. Note that the key need not to be deleted since it won't cause the user system any harm.


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