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TROJ_INJECTR.CA

October 08, 2012
 Analysis by: Cris Nowell Pantanilla
 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Spammed via email

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

32,768 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Nov 2010

Payload:

Drops files, Downloads files

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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 Trojan drops and executes the following files:

  • %User Profile%\Local Settings\VSS.EXE - also detected as TROJ_INJECTR.CA

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It injects itself into the following processes running in the affected system's memory:

  • SVCHOST.EXE

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
VSS = %User Profile%\Local Settings\VSS.EXE

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • http://{BLOCKED}.{BLOCKED}.16.115/{random}.php

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

Step 1

Scan your computer with your Trend Micro product and note files detected as TROJ_INJECTR.CA

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ Learn More ]

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\CurrentVersion\Run
    • VSS = %User Profile%\Local Settings\VSS.EXE

Step 4

Search and delete the file detected as TROJ_INJECTR.CA

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_INJECTR.CA. 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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