TROJ_ZCLICK.AA

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.

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 and executes them:

• %Application Data%\{random folder}\{random file name}.exe
• %System%\{random file name 2}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following files:

• %Windows%\Tasks\Security Center Update - {random digits}.job

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

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{random digits}
ImagePath = "%System%\{random file name 2}.exe -service "%Application Data%\{random folder}\{random file name}.exe""

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{random digits}
DisplayName = "SecurityCenterServer - {random digits}"

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
{random value} = "%Application Data%\{random folder}\{random file name}.exe"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SecurityCenterServer{random digits}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{random key 1}

HKEY_CURRENT_USER\Software\{random key 2}

It adds the following registry entries:

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

Other Details

This Trojan connects to the following possibly malicious URL:

• http://{BLOCKED}o.ru/b/{eve|opt|letr|req}/{hash}
• http://{BLOCKED}azb.ru/b/{eve|opt|letr|req}/{hash}
• http://{BLOCKED}orum.ru/b/{eve|opt|letr|req}/{hash}
• http://{BLOCKED}rray.ru/b/{eve|opt|letr|req}/{hash}
• http://{BLOCKED}r.su/b/{eve|opt|letr|req}/{hash}
• http://{BLOCKED}ror.su/b/{eve|opt|letr|req}/{hash}