Where to Buy Trend Micro Products

For Home

For Small Business

1-888-762-8736
(M-F 8:00am-5:00pm CST)

For Enterprise

1-877-218-7353
(M-F 8:00am-5:00pm CST)

Not in the United States?
Select the country/language of your choice:

Asia Pacific Region

Europe

The Americas

Not in the United States?
Select the country/language of your choice:

Asia/Pacific

Europe

America

Login

For Home

For Business

For Partners

Threat Encyclopedia

BKDR_MEVADE.A


ALIASES:

Trojan:Win32/Mevade.A(Microsoft)

PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type:Backdoor

  • Destructiveness:No

  • Encrypted: Yes

  • In the wild: Yes

OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This malware is associated with the reported increase in the number of Tor users. It has the capability to execute commands and download adware on to the infected system. Based on our research, Tor can be used to hide C&C servers.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

TECHNICAL DETAILS

File Size:

399,360 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Aug 2013

Payload:

Compromises system security, Steals information, Connects to URLs/IPs

Arrival Details

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

  • %System%\TrustedInstaller.exe
  • %System%\uti.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It drops the following non-malicious file:

  • %System%\~stg

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Autostart Technique

This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
Type = "20"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
Start = "02"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
ImagePath = "C:\WINDOWS\system32\TrustedInstaller.exe" /svc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
DisplayName = "Trusted Installer"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer
Description = "Adds, modifies, and removes applications provided as a Windows Installer (*.msi) package. If this service is disabled, any services that explicitly depend on it will fail to start."

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Trusted Installer

The scheduled task executes the malware at the following period:

  • %Windows%\Tasks\TrustedInstaller Update.job - executes the malware daily every one hour
  • %Windows%\Tasks\TrustedInstaller Update 2.job - executes the malware at system startup

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

Other System Modifications

This backdoor creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path}\{malware filename}.exe = "{malware path}\{malware filename}.exe:*:Enabled:{malware filename}.exe(in)"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\TrustedInstaller.exe = "%System%\TrustedInstaller.exe:*:Enabled:TrustedInstaller.exe(in)"

Backdoor Routine

This backdoor executes the following command(s) from a remote malicious user:

  • Perform remote connection to a certain location supplied by the remote user using SSH
  • Update copy of itself

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}statistic.net\er
  • http://{BLOCKED}ystatistic.com\er
  • http://{BLOCKED}atistic.com\er
  • http://{BLOCKED}-update.net\er
  • http://{BLOCKED}ice.net\er
  • http://{BLOCKED}-stat.com\er
  • http://{BLOCKED}statistic.net\br
  • http://{BLOCKED}ystatistic.com\br
  • http://{BLOCKED}atistic.com\br
  • http://{BLOCKED}-update.net\br
  • http://{BLOCKED}ice.net\br
  • http://{BLOCKED}-stat.com\br

NOTES:

It contains Anti Virtual Machine Execution. It checks for the presence of the following related processes

  • VirtualBox
  • VMWare

It also includes Anti-Sandbox, where it does not proceed with execution if found running on the following sandbox:

  • Sandboxie

It requires the following parameters to be able to execute properly:

  • /svc
  • /w
  • /i
  • /r

It collects the following system information, and then sends this information to the remote user:

  • UUID
  • Operating System
  • Installed AV products
  • Installed Firewall Products

SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.248.07

FIRST VSAPI PATTERN DATE:

31 Aug 2013

VSAPI OPR PATTERN File:

10.249.00

VSAPI OPR PATTERN Date:

31 Aug 2013

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

Disable this malware service

[ Learn More ]
  • Trusted Installer

Step 3

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.
  • %System%\~stg
  • %Windows%\Tasks\TrustedInstaller Update.job
  • %Windows%\Tasks\TrustedInstaller Update 2.job

Step 4

Delete this registry key

[ 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • Trusted Installer

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_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path}\{malware filename}.exe = "{malware path}\{malware filename}.exe:*:Enabled:{malware filename}.exe(in)"
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\TrustedInstaller.exe = "%System%\TrustedInstaller.exe:*:Enabled:TrustedInstaller.exe(in)"

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_MEVADE.A. 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.


Did this description help? Tell us how we did.

Featured Stories

Connect with us on