Analysis by: RonJay Kristoffer Caragay
ALIASES:

Troj/Zbot-HGR(Sophos), W32/Zbot.CETD!tr(Fortinet), Trojan-Spy.Win32.Zbot.tgyu(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: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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: 292,414 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 03 Jul 2014
Payload: Displays windows, Connects to URLs/IPs

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 drops the following copies of itself into the affected system:

  • %Application Data%\{random foldername}\{random filename 1}.exe
  • %System%\{random filename 2}.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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following files:

  • %Tasks%\Security Center Update - {number}.job

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{number}
ImagePath = ""%System%\{random filename 2}.exe" -service "%Application Data%\{random foldername}\{random filename 1}.exe""

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{number}
DisplayName = "Security Center Server - {number}"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random entry} = "%Application Data%\{random folder name}\{random filename 1}.exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random entry} = "%Application Data%\{random folder name}\{random filename 1}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{random key 1}

HKEY_CURRENT_USER\Software\{random key 2}

HKEY_LOCAL_MACHINE\SOFTWARE\{random key 2}

HKEY_LOCAL_MACHINE\SOFTWARE\{random key 1}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{number}

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SecurityCenterServer{number}\Enum

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SecurityCenterServer{number}\Security

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\{random key 2}
License = "444"

HKEY_CURRENT_USER\Software\{random key 2}
License = "444"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
{random filename 1}.exe = "11001"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}-vaper.su/b/eve/{random value}
  • http://{BLOCKED}-vaper.su/b/req/{random value}
  • http://{BLOCKED}-vaper.su/b/opt/{random value}
  • http://ds.{BLOCKED}va.com
  • http://{BLOCKED}search.com
  • http://{BLOCKED}s-search.com
  • http://{BLOCKED}search.com
  • http://{BLOCKED}tra-search.com
  • http://{BLOCKED}ring.su/
  • http://{BLOCKED}yope.su/
  • http://{BLOCKED}een.ru/
  • http://{BLOCKED}rusn.su/
  • http://{BLOCKED}-news.ru/

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.914.05
FIRST VSAPI PATTERN DATE: 10 Jul 2014
VSAPI OPR PATTERN File: 10.915.00
VSAPI OPR PATTERN Date: 11 Jul 2014

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

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • SecurityCenterServer{number}

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_LOCAL_MACHINE\SOFTWARE\{random key 2}
    • License = "444"
  • In HKEY_CURRENT_USER\Software\{random key 2}
    • License = "444"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
    • {random filename 1}.exe = "11001"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random entry} = "%Application Data%\{random folder name}\{random filename 1}.exe"
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random entry} = "%Application Data%\{random folder name}\{random filename 1}.exe"

Step 5

Search and delete these files

[ 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%\{random foldername}\{random filename 1}.exe
  • %System%\{random filename 2}.exe
  • %Tasks%\Security Center Update - {number}.job

Step 6

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

The following created files/folders/registry keys/registry entries 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 system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

  • In HKEY_CURRENT_USER\Software
    • {random key 1}
  • In HKEY_CURRENT_USER\Software
    • {random key 2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • {random key 2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • {random key 1}


Did this description help? Tell us how we did.