TSPY_ZBOT.POG

October 12, 2012

Analysis by: Nikko Tamana

ALIASES:

W32/Zbot.EQPB!tr (Fortinet), PWS:Win32/Zbot (Microsoft), a variant of Win32/Kryptik.ALRH trojan (NOD32)

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

OVERALL RISK RATING:

REPORTED INFECTION:

SYSTEM IMPACT RATING:

INFORMATION EXPOSURE:

Threat Type: Spyware
Destructiveness: No
Encrypted:
In the wild: Yes

OVERVIEW

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.

This file contains a URL where it connects to possibly download other files.

TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Initial Samples Received Date:

16 Sep 2012

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 files:

%Application Data%\{random letters 1}\{random letters}.exe - copy of itself
%Application Data%\{random letters 2}\{random letters}.{random letters} - encrypted file
%Application Data%\Microsoft\Address Book\test.wab~
%Application Data%\Microsoft\Address Book\test.wab
%User Temp%\TMP{random}.bat

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.. %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.)

It creates the following folders:

%Application Data%\{random letters 1}
%Application Data%\{random letters 2}
%Application Data%\{random letters 3}

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

Other System Modifications

This spyware adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Privacy
"CleanCookies" = "0"

HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random} =

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
(Default) = "%Application Data%\Microsoft\Address Book\test.wab"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
"OlkContactRefresh" = "0"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
"OlkFolderRefresh" = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts
"ConnectionSettingsMigrated" = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\0
"1609" = "0"