ALIASES:

Backdoor:Win32/Ciadoor.gen (Microsoft); BackDoor-ASB.svr (McAfee); PAK:UPX, Backdoor.Win32.Ciadoor.m, Backdoor.Win32.Ciadoor.m (Kaspersky); Trojan-Downloader.Win32.VB.Inject!cobra (v) (Sunbelt); Generic.Malware.SLMDBCbg.0CD73F0C (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size: 66,440 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 04 Oct 2012

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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Generic Host Process = "%System%\scvhost.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Runservices
Generic Host Process = "%System%\scvhost.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
set\set

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Runservices

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows\
Run

HKEY_CLASSES_ROOT\..DlI

It adds the following registry entries:

HKEY_CURRENT_USER\Software\VB and VBA Program Settings\
set\set
set = "KoQ83oTaG6.ini"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Generic Host Process = "%System%\scvhost.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows\
Run
Generic Host Process = "%System%\scvhost.exe"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{E14DCE67-8FB7-4721-8149-179BAA4D792C}

Dropping Routine

This backdoor drops the following files:

  • %System%\KoQ83oTaG6.ini
  • %System%\scvhost.exe

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

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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 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_CURRENT_USER\Software\VB and VBA Program Settings
    • set
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion
    • Runservices
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\Explorer
    • Run
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
    • Run
  • In HKEY_CLASSES_ROOT
    • ..DlI

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\Windows\CurrentVersion\Run
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Runservices
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_CURRENT_USER\Software\VB and VBA Program Settings\set\set
    • set = "KoQ83oTaG6.ini"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • Generic Host Process = "%System%\scvhost.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows\Run
    • Generic Host Process = "%System%\scvhost.exe"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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%\KoQ83oTaG6.ini
  • %System%\scvhost.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_CIADOOR.X. 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 7

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
    • {E14DCE67-8FB7-4721-8149-179BAA4D792C}


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