BKDR_PERCS.A

This malware is related to an attack that took advantage of legitimate services like Google Drive and Dropbox in order to look less suspicious to unwary users.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor may be unknowingly downloaded by a user while visiting malicious websites.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It logs a user's keystrokes to steal information.

Arrival Details

This backdoor may be unknowingly downloaded by a user while visiting malicious websites.

Installation

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

• %Application Data%\scvperc.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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
scvperc = "%Application Data%\scvperc.exe"

Backdoor Routine

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

• Download and execute arbitrary file in %User Temp%
• Remote command prompt
• Get drive information

(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.)

It connects to the following websites to send and receive information:

• {BLOCKED}i.{BLOCKED}2.com:32040

Dropping Routine

This backdoor drops the following file(s), which it uses for its keylogging routine:

• %Application Data%\Logs\{date-month-year} - encrypted

(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.)

Information Theft

This backdoor attempts to steal stored email credentials from the following:

• Windows Live
• Mozilla Thunderbird
• Outlook

It attempts to get stored information such as user names, passwords, and hostnames from the following browsers:

• Mozilla Firefox
• Opera
• Internet Explorer
• Google Chrome
• Chromium

It logs a user's keystrokes to steal information.