TROJANSPY.WIN32.ZBOT.AD

 Analysis by: Arvin Roi Macaraeg

 ALIASES:

Trojan.Win32.Inject.vcbd(KASPERSKY), Win32/Spy.Zbot.ACB trojan(NOD32)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It steals certain information from the system and/or the user.

It connects to certain websites to send and receive information. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 Dec 2018

Payload:

Connects to URLs/IPs, Drops files

Arrival Details

This Trojan Spy 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 Spy drops the following copies of itself into the affected system and executes them:

  • %Application Data%\{Random Folder 1}\{Random Filename 1}.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, 7, and 8.)

It drops the following files:

  • %Application Data%\{Random Folder 2}\{Random Filename 2}.{Random Extension}
  • %User Temp%\tmp{random}.bat - Used to delete initially executed copy of itself

(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, 7, and 8.. %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, 7, and 8.)

It creates the following folders:

  • %Application Data%\{Random Folder 1}
  • %Application Data%\{Random Folder 2}

(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, 7, and 8.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Local\{GUID}
  • Global\{GUID}

It injects codes into the following process(es):

  • explorer.exe

Autostart Technique

This Trojan Spy 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 1}\{Random Filename 1}.exe"

Other System Modifications

This Trojan Spy adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
{Random Key}
{Random Value Name} = {Hex Data}

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = 0

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableSPDY3_0 = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
Enabled = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV8 = 0

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\PhishingFilter
EnabledV9 = 0

Information Theft

This Trojan Spy steals the following information:

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

Other Details

This Trojan Spy connects to the following website to send and receive information:

  • https://{BLOCKED}ure.com/s186/kwz.jpg

It does the following:

  • Receive configuration file.
    The received 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. Note that the contents of the file, hence the list of websites to monitor, may change anytime.
  • However, as of this writing, the file is not downloadable even though the site is alive.

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.696.02

FIRST VSAPI PATTERN DATE:

18 Dec 2018

VSAPI OPR PATTERN File:

14.697.00

VSAPI OPR PATTERN Date:

19 Dec 2018

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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\{Random Key}
    • {Random Value Name} = {Hex Data}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnonBadCertRecving = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableSPDY3_0 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter
    • Enabled = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter
    • EnabledV8 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\PhishingFilter
    • EnabledV9 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • {GUID} = "%Application Data%\{Random Folder 1}\{Random Filename 1}.exe"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJANSPY.WIN32.ZBOT.AD. 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 6

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.

  • HKEY_CURRENT_USER\Software\Microsoft\{Random Key}
    • {Random Value Name} = {Hex Data}
  • %Application Data%\{Random Folder 1}
  • %Application Data%\{Random Folder 2}
  • %Application Data%\{Random Folder 2}\{Random Filename 2}.{Random Extension}

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJANSPY.WIN32.ZBOT.AD. 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 the following Trend Micro Support pages for more information:


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