BKDR_CADELSPY.A

 Analysis by: Mar Philip Elaurza

 ALIASES:

Backdoor.Cadelspy (Symantec); Trojan:Win32/Skeeyah.A!bit (Microsoft); Trojan-Dropper.Win32.Demp.aldr (Kaspersky)

 PLATFORM:

Windows

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

  • 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 steals system information. It logs a user's keystrokes to steal information.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

631,808 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Nov 2015

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 files:

  • %User Temp%\ldr32_x86.exe - deletes the folder (%User Temp%\_tmp001) and files in it for 32-bit Operating System after dropping in %System% folder
  • %User Temp%\ldr32_x64.exe - deletes the folder (%User Temp%\_tmp001) and files in it for 64 bit Operation System after dropping in %System% folder
  • %User Temp%\_tmp001\work.path
  • %User Temp%\_tmp001\x86\ntsvc32.dll
  • %User Temp%\_tmp001\x86\ntsvcst32.dll
  • %User Temp%\_tmp001\x86\2093110702.cfg
  • %User Temp%\_tmp001\x86\2093110702.rou
  • %User Temp%\_tmp001\x64\ntsvc32.dll
  • %User Temp%\_tmp001\x64\ntsvcst32.dll
  • %User Temp%\_tmp001\x64\2093110702.cfg
  • %User Temp%\_tmp001\x64\2093110702.rou
  • %System%\ntsvc32\ntsvc32.dll
  • %System%\ntsvc32\ntsvcst32.dll
  • %System%\ntsvc32\2093110702.cfg
  • %System%\ntsvc32\2093110702.rou

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It creates the following folders:

  • %Fonts%\ntpath\
  • %Fonts%\ntpath\completed\
  • %Fonts%\ntpath\completed\p[number]\
  • %Fonts%\ntpath\completed\upl\
  • %User Temp%\_tmp001\
  • %User Temp%\_tmp001\x86\
  • %User Temp%\_tmp001\x64\
  • %System%\ntsvc32\

(Note: %Fonts% is the Fonts folder, where it usually is C:\Windows\Fonts on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = %System%\ntsvc32\ntsvcst32.dll

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
LoadAppInit = 1

Download Routine

This backdoor connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}inpros.com/allusers/2093110702.rou.2093110702.txt

Information Theft

This backdoor steals system information.

It logs a user's keystrokes to steal information.

Stolen Information

This backdoor saves the stolen information in the following file:

  • %Fonts%\ntpath\completed\p[number]\2093110702-({Current Date})-(05-15-36)-006.fjr_0001.ecm
  • %Fonts%\ntpath\completed\upl\2093110702-({Current Date})-(05-15-25)-003.fjr_0001.ecm

(Note: %Fonts% is the Fonts folder, where it usually is C:\Windows\Fonts on all Windows operating system versions.)

It sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}inpros.com/scripts/uploader.aspx

Other Details

This backdoor deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.180.05

FIRST VSAPI PATTERN DATE:

29 Nov 2015

VSAPI OPR PATTERN File:

12.181.00

VSAPI OPR PATTERN Date:

30 Nov 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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 NT\CurrentVersion\Windows
    • AppInit_DLLs = %System%\ntsvc32\ntsvcst32.dll
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • LoadAppInit = 1

Step 5

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.
  • %User Temp%\ldr32_x86.exe
  • %User Temp%\ldr32_x64.exe
  • %System%\ntsvc32\ntsvc32.dll
  • %System%\ntsvc32\ntsvcst32.dll
  • %System%\ntsvc32\2093110702.cfg
  • %System%\ntsvc32\2093110702.rou
  • %Fonts%\ntpath\completed\p[number]\2093110702-({Current Date})-(05-15-36)-006.fjr_0001.ecm
  • %Fonts%\ntpath\completed\upl\2093110702-({Current Date})-(05-15-25)-003.fjr_0001.ecm

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Fonts%\ntpath\
  • %Fonts%\ntpath\completed\
  • %Fonts%\ntpath\completed\p[number]\
  • %Fonts%\ntpath\completed\upl\
  • %System%\ntsvc32\

Step 7

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


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