TSPY_ZBOT.UUK

 Analysis by: Jennifer Gumban

 ALIASES:

Trojan-Spy.Win32.Zbot.qavo (Kaspersky), PWS:Win32/Zbot (Microsoft)

 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:
 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.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size:

475,136 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

25 Sep 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 drops the following files:

  • %Application Data%\Microsoft\Address Book\{user name}.wab

(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.)

It drops the following copies of itself into the affected system:

  • %Application Data%\{random folder}\{random}.exe

(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.)

It creates the following folders:

  • %Application Data%\Microsoft\Address Book
  • %Application Data%\{random folder}

(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.)

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} = "%Application Data%\{random folder}\{random}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft
WAB = ""

HKEY_CURRENT_USER\Software\Microsoft
{random} = ""

HKEY_CURRENT_USER\Software\Microsoft\
WAB
WAB4 = ""

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random} = "{random}"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkContactRefresh = "0"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkFolderRefresh = "0"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
(Default) = "%Application Data%\Microsoft\Address Book\{user name}.wab"

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
2427:TCP = "2427:TCP:*:Enabled:TCP 2427"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
4353:UDP = "4353:UDP:*:Enabled:UDP 4353"

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

NOTES:

This spyware connects to randomly-generated IP addresses.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.302.03

FIRST VSAPI PATTERN DATE:

25 Sep 2013

VSAPI OPR PATTERN File:

10.303.00

VSAPI OPR PATTERN Date:

26 Sep 2013

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

Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.UUK

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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
    • {random} = ""
  • In HKEY_CURRENT_USER\Software\Microsoft
    • WAB = ""
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB
    • WAB4 = ""
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • Wab File Name = ""

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
    • {GUID} = "%Application Data%\{random folder}\{random}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\{random}
    • {random} = "{random}"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • OlkContactRefresh = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • OlkFolderRefresh = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4\Wab File Name
    • (Default) = "%Application Data%\Microsoft\Address Book\{user name}.wab"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 2427:TCP = "2427:TCP:*:Enabled:TCP 2427"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 4353:UDP = "4353:UDP:*:Enabled:UDP 4353"

Step 6

Search and delete this file

[ Learn More ]
There may be some files 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.
  • %Application Data%\Microsoft\Address Book\{user name}.wab

Step 7

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.
  • %Application Data%\Microsoft\Address Book
  • %Application Data%\{random folder}

Step 8

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