Modified by: Jaime Benigno Reyes
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

It does not have any propagation routine.

  TECHNICAL DETAILS

File Size: 8,704 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 07 Jan 2015
Payload: Connects to URLs/IPs, Downloads files

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 copies of itself into the affected system:

  • {All Users' My Pictures folder}\AcroRd32Info.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
AccroRd32info = "{All Users' My Pictures folder}\AcroRd32Info.exe"

Propagation

This Trojan does not have any propagation routine.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}ion-sas.com/red/image/index.php
  • http://www.{BLOCKED}ion-sas.com/red/image/index.php

It saves the files it downloads using the following names:

  • %User Temp%\Perdata{random number}.dat - deleted afterwards

(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.)

NOTES:

It drops the following file as part of decrypting the contents of Perdata{random number}.dat:

  • %User Temp%\Perdata{random number}.b6 - deleted afterwards

It drops the following final output file:

  • %User Temp%\Perdata{random number}.exe

It executes this file if the file type is executable by determining the header in its code.

As of writing, the sites it accessed that are mentioned above only display the current day, date, and time.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 11.396.02
FIRST VSAPI PATTERN DATE: 07 Jan 2015
VSAPI OPR PATTERN File: 11.397.00
VSAPI OPR PATTERN Date: 08 Jan 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • AccroRd32info = "{All Users' My Pictures folder}\AcroRd32Info.exe"

Step 4

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%\Perdata{random number}.b6
  • %User Temp%\Perdata{random number}.dat
  • %User Temp%\Perdata{random number}.exe

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADER.SBF. 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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