BKDR_BLACKHOLE.E

May 10, 2013
 ALIASES:

Backdoor:Win32/Blackhole.J (Microsoft); BackDoor-CGX.svr (McAfee); Backdoor.Singu (Symantec); Backdoor.Win32.BlackHole.qye (Kaspersky); BehavesLike.Win32.Malware.wsc (mx-v) (Sunbelt); Trojan horse BackDoor.Generic2.ZXA (AVG)

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

206,278 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

10 May 2013

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:

  • %Windows%\ssytem.exe

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

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
WinOldApp

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodial = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodisconnect = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodial = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableAutodisconnect = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Hardware Profiles\0001\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
EnableAutodial = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Hardware Profiles\0001\Software\
Microsoft\windows\CurrentVersion\
Internet Settings
EnableAutodisconnect = "{random values}"

It modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\International
sDate = "-"

(Note: The default value data of the said registry entry is /.)

Dropping Routine

This backdoor drops the following files:

  • %System Root%\$$a$$.bat
  • %Windows%\ssytem.cfg
  • %System%\KeySpy.dll

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Windows% is the Windows folder, which is usually C:\Windows.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This backdoor deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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\Policies
    • WinOldApp

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\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableAutodisconnect = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableAutodisconnect = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • EnableAutodial = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Hardware Profiles\0001\Software\Microsoft\windows\CurrentVersion\Internet Settings
    • EnableAutodisconnect = "{random values}"

Step 4

Restore these modified registry values

[ 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\Control Panel\International
    • From: sDate = "-"
      To: sDate = ""/""

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 Root%\a.bat
  • %Windows%\ssytem.cfg
  • %System%\KeySpy.dll
a.bat
  • %Windows%\ssytem.cfg
  • %System%\KeySpy.dll
    •
  • In the Look In drop-down list, select My Computer then press Enter.
  • Once located, select the file then press SHIFT+DELETE to delete it.
  • Repeat the said steps for all files listed.

    • • For Windows Vista and Windows 7 users:

    1. Click Start>Computer.
    2. In the Search input box, type:
      • %System Root%\a.bat
      • %Windows%\ssytem.cfg
      • %System%\KeySpy.dll
    3. Once located, select the file then press SHIFT+DELETE to delete it.
    4. Repeat the said steps for all files listed.
      *Note: Read the following Microsoft page if these steps do not work on Windows 7.

    Step 6

    Scan your computer with your Trend Micro product to delete files detected as BKDR_BLACKHOLE.E. 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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