PE_VIRUX.GEN-4
W32.Ramnit (Symantec); Trojan.Win32.Lebag.ecm (Kaspersky); Trojan-Spy.Win32.Zbot.gen.y.2 (v) (Sunbelt); Win32.Ramnit.J (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: File infector
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
57,344 bytes
EXE
30 Sep 2011
Arrival Details
This file infector 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 file infector drops the following copies of itself into the affected system:
- %Program Files%\Microsoft\WaterMark.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
It creates the following folders:
- %Program Files%\Microsoft
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
Autostart Technique
This file infector modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,,%Program Files%\microsoft\watermark.exe"
(Note: The default value data of the said registry entry is %System%\userinit.exe,.)
Other System Modifications
This file infector deletes the following files:
- %Program Files%\Microsoft\px1.tmp
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
Dropping Routine
This file infector drops the following files:
- %Program Files%\Microsoft\px1.tmp
- %System%\dmlconf.dat
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
This report is generated via an automated analysis system.
SOLUTION
9.200
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Identify and delete files detected as PE_VIRUX.GEN-4 using either the Startup Disk or Recovery Console
Step 3
Restore this modified registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Userinit="%System%\userinit.exe,,%Program Files%\microsoft\watermark.exe"
To: Userinit=%System%\userinit.exe,
- From: Userinit="%System%\userinit.exe,,%Program Files%\microsoft\watermark.exe"
Step 4
Search and delete this folder
Step 5
Search and delete these files
- %Program Files%\Microsoft\px1.tmp
- %System%\dmlconf.dat
Step 6
Scan your computer with your Trend Micro product to clean files detected as PE_VIRUX.GEN-4. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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