ALIASES:

Backdoor:Win32/Drixed.A (Microsoft); BackDoor-FCGF!1F07F5DBB22D (McAfee); Trojan Horse (Symantec); Trojan.Win32.Yakes.gyfy (Kaspersky); Win32.Malware!Drop (Sunbelt); Trojan horse Crypt3.BBKY (AVG)

 PLATFORM:

Windows

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 65,536 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 11 Nov 2014

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.

Other System Modifications

This backdoor deletes the following files:

  • %Application Data%\edg1.tmp

(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 registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{6CFEAC31-098B-AE11-14D8-5D480AA37CEB}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{03BED620-1813-B0C5-E408-1EE8D797C2AC}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{C9E513FB-CCB7-DCA2-E3DA-94FD2C78BB08}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{6531F893-DDB3-FDCB-0AC2-95C2B843D67F}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{93699F03-C12B-CC88-0BD6-98371ADC240D}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{21A7B1C0-E902-184A-1A62-45AC02A34CBA}\ShellFolder

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{44112592-9055-BE27-97A6-C04090FF9268}\ShellFolder

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{44112592-9055-BE27-97A6-C04090FF9268}\ShellFolder
01CFF6424FAEDACC = "{random values}"

Dropping Routine

This backdoor drops the following files:

  • %Application Data%\4.tmp

(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.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}.117.207

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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

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\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{6CFEAC31-098B-AE11-14D8-5D480AA37CEB}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{03BED620-1813-B0C5-E408-1EE8D797C2AC}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{C9E513FB-CCB7-DCA2-E3DA-94FD2C78BB08}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{6531F893-DDB3-FDCB-0AC2-95C2B843D67F}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{93699F03-C12B-CC88-0BD6-98371ADC240D}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{21A7B1C0-E902-184A-1A62-45AC02A34CBA}
    • ShellFolder
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{44112592-9055-BE27-97A6-C04090FF9268}
    • ShellFolder

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\CurrentVersion\Explorer\CLSID\{44112592-9055-BE27-97A6-C04090FF9268}\ShellFolder
    • 01CFF6424FAEDACC = "{random values}"

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%\4.tmp

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_DRIXED.BM. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Application Data%\edg1.tmp


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