WORM_PHORPIEX.DA

This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

Arrival Details

This worm arrives via removable drives.

It 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 worm adds the following folders:

• %Application Data%\Microsoft-Driver-8875-2355-97567
• {Removable Drive Letter}:\{random numbers}

(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.)

It drops the following copies of itself into the affected system and executes them:

• %Application Data%\Microsoft-Driver-8875-2355-97567\winrcdsvn.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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
DefaultMSRDSettings = "%Application Data%\Microsoft-Driver-8875-2355-97567\winrcdsvn.exe

Other System Modifications

This worm creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Application Data%\Microsoft-Driver-8875-2355-97567\winrcdsvn.exe = "%Application Data%\Microsoft-Driver-8875-2355-97567\winrcdsvn.exe:*:Enabled:DefaultMSRDSettings"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

• {Removable Drive Letter}:\usbdrvsn.exe
• {Removable Drive Letter}:\{random numbers}\{Folder Names}.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
icon=%SystemRoot%\system32\SHELL32.dll,4
action=Open folder to view files
shellexecute=usbdrvsn32.exe
UseAutoPlay=1

Other Details

This worm connects to the following possibly malicious URL:

• http://{BLOCKED}ok-o.com
• http://{BLOCKED}ok-t.com

NOTES:
This worm creates .LNK (shortcut) files pointing to its copy, {Removable Drive Letter}:\{random numbers}\{Folder Names}.exe. {Folder Names} are the names found at the root of the removable drive, if there are any. It then sets the attribute of the said folders to Hidden.