BKDR_AGENT.DMS

This backdoor 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 backdoor 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 backdoor creates the following folders:

• %User Profile%\Application Data\Common Files
• %User Profile%\Microsoft\Plugins
• %User Profile%\Common Files\Plugins

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

Other System Modifications

This backdoor deletes the following files:

• %User Temp%\tst2.tmp
• %User Temp%\tst4.tmp
• %User Temp%\tst5.tmp
• %User Temp%\tst6.tmp
• %User Temp%\tst7.tmp
• %User Temp%\tst1.tmp
• %User Temp%\tst3.tmp
• %User Temp%\tst8.tmp
• %User Temp%\tst9.tmp
• %User Temp%\tstA.tmp

(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.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Options

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Text

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\RTF

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Word6

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Write

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\IP

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Recent File List

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad\Settings

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Applets\
Wordpad

Dropping Routine

This backdoor drops the following files:

• %User Temp%\trifcs.exe
• %User Temp%\20120420.doc
• %User Temp%\ms4859.tmp
• %User Temp%\ms4901.tmp

(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.)

Other Details

This backdoor connects to the following possibly malicious URL:

• http://touber.{BLOCKED}a.net/_vti_y2/index.html?{random characters}

This report is generated via an automated analysis system.