BKDR_YAYIH.AB

This backdoor may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system.

Arrival Details

This backdoor may be dropped by other malware.

Installation

This backdoor drops the following copies of itself into the affected system:

• %Program Files%\Common Files\{malware filename}.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• abcdef

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
common = "{malware path and file name}"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Create files
• Execute command shell
• Terminate itself

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• {BLOCKED}nuser.ISAsecret.com

Other Details

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

• %Application Data%\aumLib.ini

(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.)

NOTES:

It sends system information such as use rname, IP address, and OS version to the following URL:

• http://domainuser.ISAsecret.com/bbs/info.asp