TSPY_ZBOT.YUYAM

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.

As of this writing, the said sites are inaccessible.

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:

• %Application Data%\wsdfvsxr\wsdfvsxe.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 drops the following files:

• %Application Data%\wsdfvsxr\wsdfvsxe.bat
• %Application Data%\{random 1}\{random filename 1}.exe <-- detected as TSPY_ZBOT.SMJV
• %User Temp%\FB_{characters 1}.tmp.exe <-- detected as TSPY_ZBOT.SMJV
• %User Temp%\FB_{characters 2}.tmp.exe

It drops the following non-malicious files:

• %User Temp%\FB_{characters 1}.tmp
• %User Temp%\FB_{characters 2}.tmp
• %Application Data%\{random 2}\{random filename 2}.{random ext}
• %Application Data%\Microsoft\Address Book\{user name}.wab
• %Application Data%\Microsoft\Address Book\{user name}.wab~
• %AppDataLocal%\Identities\{CLSID}\Microsoft\Outlook Express\Folders.dbx
• %AppDataLocal%\Identities\{CLSID}\Microsoft\Outlook Express\Inbox.dbx
• %AppDataLocal%\Identities\{CLSID}\Microsoft\Outlook Express\Offline.dbx
• %AppDataLocal%\Identities\{CLSID}\Microsoft\Outlook Express\Sent Items.dbx
• %Application Data%\{random 2}\{random filename 2}.tmp
• %Application Data%\dclogs\{date}-2.dc

(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.. %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.. %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:

• %Application Data%\wsdfvsxr
• %User Profile%\Application Data\{random 1}
• %User Profile%\Application Data\{random 2}
• %Application Data%\Microsoft\Address Book
• %Application Data%\Identities\{CLSID}
• %Application Data%\Identities\{CLSID}\Microsoft
• %Application Data%\Identities\{CLSID}\Microsoft\Outlook Express
• %Application Data%\dclogs

(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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It injects itself into the following processes as part of its memory residency routine:

• %Windows%\explorer.exe

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

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 CLSID} = "%Application Data%\{random 1}\{random filename 1}.exe"

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

• %User Startup%\wsdfvsx.vbs

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
WAB

HKEY_CURRENT_USER\Software\DC3_FEXEC

HKEY_CURRENT_USER\Software\Microsoft\
{random characters}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
FirstRun = 1

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

HKEY_CURRENT_USER\Software\Microsoft\
{random characters}
{random characters} = {hex values}

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:

• http://{BLOCKED}oovesi.org/pam/upload/config.bin

As of this writing, the said sites are inaccessible.

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.