TROJ_BLACKREV.AD

January 22, 2015
 Analysis by: Michael John Marcos
 ALIASES:

Trojan-Dropper.Win32.Dapato.ccqg (Kaspersky), a variant of Win32/TrojanDownloader.Delf.RTF (Eset), Mal/DelpDldr-C (Sophos)

 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

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

  TECHNICAL DETAILS

File Size:

23,552 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Apr 2013

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %Application Data%\system.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • exchangedropt

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = system.exe

Download Routine

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

  • http://{BLOCKED}a.ru/tui/gate.php?cmd=getexe

Information Theft

This Trojan accesses the following site to download its configuration file:

  • http://{BLOCKED}a.ru//tui/gate.php?cmd=getinstallconfig

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

9.862.04

FIRST VSAPI PATTERN DATE:

30 Mar 2015

VSAPI OPR PATTERN File:

9.863.00

VSAPI OPR PATTERN Date:

30 Mar 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

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_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • run = system.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.
  • %Application Data%\system.exe

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_BLACKREV.AD. 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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