Analysis by: Pearl Charlaine Espejo
ALIASES:

Rogue:Win32/FakeRean (Microsoft); FraudTool.Win32.FakeRean (Vipre); Trojan-FakeAV.Win32.Agent.ircb (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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 displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

  TECHNICAL DETAILS

File Size: 1,177,680 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Mar 2015
Payload: Connects to URLs/IPs, Displays message/message boxes, Terminates processes

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 and executes the following files:

  • %Application Data%\diess.exe
  • %User Temp%\d.bat - batch file that will delete the executed file

(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.. %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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • AntiVirus Pro 2015_MUTEX

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
AntiVirus Pro 2015 = "%Application Data%\diess.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
diess.exe = "%Application Data%\diess.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{random}

Rogue Antivirus Routine

This Trojan displays fake alerts that warn users of infection. It also displays fake scanning results of the affected system. It then asks for users to purchase it once scanning is completed. If users decide to purchase the rogue product, users are directed to a certain website asking for sensitive information, such as credit card numbers.

NOTES:

This Trojan terminates processes except the following:

  • audiodg.exe
  • conhost.exe
  • consent.exe
  • control.exe
  • csrss.exe
  • ctfmon.exe
  • diess exe
  • dllhost.exe
  • dwm.exe
  • dwwin.exe
  • logonui.exe
  • lsass.exe
  • lsm.exe
  • mcagent.exe
  • MpfSrv.exe
  • msimn.exe
  • route.exe
  • SLsvc.exe
  • slui.exe
  • smss.exe
  • spoolsv.exe
  • svchost.exe
  • System
  • taskeng.exe
  • vmnat.exe
  • wininit.exe
  • winmgmt.exe
  • wscntfy.exe
  • WsHost.exe

It sends a GET request for the resource:

  • http://{BLOCKED}anna.com/images/s.php?id=241

Once launched, it shows a window where it imitates a system scan and displays false scanning results:

It also shows false firewall notifications:

It periodically displays the following message in the system tray:

It also displays the following activation dialog box:

Upon clicking Activate Now, it connects to the following URLs to ask for payment:

  • http://{BLOCKED}rem.com/{parameters}
  • http://secure.{BLOCKED}auto.com:443

It then opens a fake antivirus purchase page:

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.556.03
FIRST VSAPI PATTERN DATE: 20 Mar 2015
VSAPI OPR PATTERN File: 11.557.00
VSAPI OPR PATTERN Date: 21 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

Scan your computer with your Trend Micro product and note files detected as TROJ_FAKEAV.YSXF

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete these files

[ 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%\d.bat

Step 5

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
    • diess.exe = "%Application Data%\diess.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • AntiVirus Pro 2015 = "%Application Data%\diess.exe"

Step 6

Delete this registry key

[ Learn More ]

=Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software
    • {random}

Step 7

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