PE_VIRUX.S-4

This file infector infects target host files via Cavity-Appending infection technique.

It hooks APIs so that when these APIs are called, the virus code is executed which then infect files.

It does not infect files with certain characteristics.

It also searches for target script files for iframe infection. Infected script files are detected as HTML_IFRAME.SMV.

It connects to certain IRC servers and attempts to join a certain channel to receive and execute commands on the affected system.

As of this writing, no reply has been received from the servers.

This file infector may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

It connects to Internet Relay Chat (IRC) servers.

Arrival Details

This file infector may be dropped by other malware.

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

Installation

This file infector injects threads into the following normal process(es):

• WINLOGON.EXE

Other System Modifications

This file infector also creates the following registry entry(ies) as part of its installation routine:

HKEY_USERS\.DEFAULT\SOFTWARE\
Microsoft\Windows\CurrentVersion\
Explorer
UpdateHost = {random binary value}

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
\??\%System%\winlogon.exe = \??\%System\winlogon.exe:*:enabled:@shell32.dll,-1

File Infection

This file infector infects the following file types:

• EXE
• SCR

It avoids infecting files that contain the following strings in their names:

• OTSP
• WC32
• WCUN
• WINC

Backdoor Routine

This file infector connects to any of the following Internet Relay Chat (IRC) servers:

• ilo.{BLOCKED}z.pl
• ant.{BLOCKED}z.pl

HOSTS File Modification

This file infector adds the following strings to the Windows HOSTS file:

• 127.0.0.1 www.{BLOCKED}z.pl

Other Details

Based on analysis of the codes, it has the following capabilities:

• It infects target host files via Cavity-Appending infection technique.
• It hooks the following APIs so that when these APIs are called, the virus code is executed which will then infect files:
  • NtCreateFile
  • NtOpenFile
  • NtCreateProcess
  • NtCreateProcessEx
  • NtQueryInformationProcess
• It does not infect files with the following characteristics:
  • .DLL files
  • PE Files with _win section name
  • Files with infection marker
• It also infects script files by first checking if the target script file's extension name is any of the following:
  • ASP
  • HTM
  • PHP
• Once it finds target script files, it creates a flag for the file for iframe infection. It opens flagged files then checks for a certain string in the file. If it finds that string, it skips the file. If not, then it proceeds with the infection of the file.
• It then looks for the string in the target script file. Once found, it infects script files by inserting the malicious iframe code below:
  
• It returns execution to the host file's original code after execution. Infected script files are detected as HTML_IFRAME.SMV.
• As of this writing, no reply from the server has been received.