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TROJ_SCAR.YZ

October 12, 2012
 ALIASES:

Generic BackDoor!dsh (McAfee); Trojan.Gen (Symantec); Backdoor.Win32.Albot.ab (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan.Generic.KDV.348225 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • 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:

120,832 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

09 Apr 2012

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:

  • %User Profile%\Application Data\AudioTreiber_x64.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}
IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe /ActiveX"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://effect.{BLOCKED}c.ru/panel/aldi/gate.php/gate.php?{random characters}

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}

Step 4

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\SOFTWARE\Microsoft\Active Setup\Installed Components\{RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}
    • IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe /ActiveX"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • IWpI4Sb0nAGxDkL = "%User Profile%\Application Data\AudioTreiber_x64.exe"

Step 5

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

Step 6

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components
    • {RhsHJXCs-mzVP-Anjk-ObHO-1Z5jtTOeVC1k}


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