Skip to content

Export page to PDF
TSPY_ZBOT.YYMV
Aliases: Troj/Zbot-IKD (Sophos) ,Trojan horse Zbot.JHN (AVG) ,W32/Zbot.TAZG!tr (Fortinet) ,Trojan.Crypt (Ikarus) ,Trojan-Spy.Win32.Zbot.tazg (Kaspersky) ,PWS:Win32/Zbot (Microsoft) ,RDN/Generic PWS.y!zt (McAfee) ,Win32/Spy.Zbot.AAU trojan (Eset) ,Trojan.Win32.Generic!BT (Sunbelt)
Malware type: Spyware
Destructive: No
Platform: Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Encrypted: Yes
In the wild: Yes

Overview


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

This malware was used in a spam campaign that uses Dropbox as a social engineering lure in order for users to click the related links.

To get a one-glance comprehensive view of the behavior of this Spyware, refer to the Threat Diagram shown below.

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 may be downloaded by other malware/grayware from remote sites.

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

It deletes itself after execution.

Technical Details


File size: 687,616 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 04 Jun 2014
Payload: Downloads files, 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.

It may be downloaded by the following malware/grayware from remote sites:

  • TROJ_UPATRE.YYMV

Installation

This spyware drops the following file(s)/component(s):

  • %System%\drivers\{random filename 2}.sys - detected as RTKT_NECURS.MJYE

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

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

  • %User Temp%\{random folder name}\{random filename 1}.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.)

It drops the following non-malicious file:

  • %AppDataLocal%\{random filename 3}.{random extension}

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.)

It creates the following folders:

  • %User Temp%\{random folder name}

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random filename 1} = "%User Temp%\{random folder name}\{random filename 1}.exe"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
DisplayName = "{random filename 1}.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
Group = "Boot Bus Extender"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
ImagePath = "%System%\drivers\{random filename 2}.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
Start = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
Tag = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}
Type = "1"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random filename 2}

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random}

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
{random port 1}:UDP = "{random port 1}:UDP:*:Enabled:UDP {random port 1}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{random port 2}:TCP = "{random port 2}:TCP:*:Enabled:TCP {random port 2}"

Download Routine

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

  • http://{pseudorandom domain name}.info
  • http://{pseudorandom domain name}.com
  • http://{pseudorandom domain name}.biz
  • http://{pseudorandom domain name}.net
  • http://{pseudorandom domain name}.org
  • http://{pseudorandom domain name}.ru

Information Theft

This spyware 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 cerificates

Other Details

This spyware deletes itself after execution.

NOTES:

This spyware attempts to download its configuration file by connecting to randomly generated URLs.

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.

Solution


Minimum scan engine: 9.700
First VSAPI Pattern File: 10.840.03
First VSAPI Pattern Release Date: 04 Jun 2014
VSAPI OPR Pattern Version: 10.841.00
VSAPI OPR Pattern Release Date: 04 Jun 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

Remove malware/grayware files dropped/downloaded by TSPY_ZBOT.YYMV. (Note: Please skip this step if the threats listed below have already been removed.)

Step 3

Remove the malware/grayware file that dropped/downloaded TSPY_ZBOT.YYMV. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 4

Restart in Safe Mode

[ Learn more ]

Step 5

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • {random filename 2}

Step 6

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
    • {random filename 1} = "%User Temp%\{random folder name}\{random filename 1}.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • {random port 1}:UDP = "{random port 1}:UDP:*:Enabled:UDP {random port 1}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • {random port 2}:TCP = "{random port 2}:TCP:*:Enabled:TCP {random port 2}"

Step 7

Search and delete this folder

[ 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 Temp%\{random folder name}

Step 8

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.
  • %AppDataLocal%\{random filename 3}.{random extension}

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.YYMV. 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 10

The following created registry key(s) 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 of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:

  • HKEY_CURRENT_USER\Software\Microsoft\{random}


Did this description help? Tell us how we did.

Connect with us on