TROJ_DROPPR.NRF

November 04, 2014
 Analysis by: Francis Xavier Antazo
 ALIASES:

Exploit.Win32.CVE-2012-0158.aw (KASPERSKY), Trojan horse Exploit_c.ABCC (AVG)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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

File Size:

337,918 bytes

File Type:

DOC

Memory Resident:

No

Initial Samples Received Date:

29 Oct 2014

Arrival Details

This Trojan 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 the following files:

  • %User Temp%\1{random letter}.tmp
  • %User Temp%\RarSFX0\RasTls.dll
  • %User Temp%\RarSFX0\RasTls.dll.mcs
  • %User Temp%\RarSFX0\RasTls.exe
  • %All Users Profile%\temp\RasTls.dll
  • %All Users Profile%\temp\RasTls.dll.mcs
  • %All Users Profile%\temp\RasTls.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 creates the following folders:

  • %User Temp%\RarSFX0\

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.242.02

FIRST VSAPI PATTERN DATE:

29 Oct 2014

VSAPI OPR PATTERN File:

11.243.00

VSAPI OPR PATTERN Date:

30 Oct 2014

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\RarSFX0\RasTls.dll
  • %User Temp%\RarSFX0\RasTls.dll.mcs
  • %User Temp%\RarSFX0\RasTls.exe
  • %All Users Profile%\temp\RasTls.dll
  • %All Users Profile%\temp\RasTls.dll.mcs
  • %All Users Profile%\temp\RasTls.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPR.NRF. 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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