Analysis by: Michael Cabel
 Modified by: Abraham Latimer Camba
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This Trojan may be dropped by other malware.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 68,096 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 19 Sep 2012
Payload: Drops files

Arrival Details

This Trojan may be dropped by the following malware:

Autostart Technique

This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
conost = "%User Profile%\Application Data\Microsoft\conost.exe"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\Microsoft\conost.exe - detected by Trend Micro as BKDR_DEMTRAN.RE

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

This Trojan deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.406.03
FIRST VSAPI PATTERN DATE: 19 Sep 2012
VSAPI OPR PATTERN File: 9.407.00
VSAPI OPR PATTERN Date: 19 Sep 2012

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

Remove the malware/grayware file that dropped/downloaded TROJ_DROPER.RE

Step 3

Remove malware files dropped/downloaded by TROJ_DROPER.RE

Step 4

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • conost = "%User Profile%\Application Data\Microsoft\conost.exe"

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPER.RE. 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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