Modified by: Arvin Roi Macaraeg

ALIASES:

Win32/Farfli.CJT trojan(NOD32); VirTool:Win32/CeeInject.TD!bit(MICROSOFT)

 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size: 113,664 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 28 May 2019

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:

  • %Program Files%\java.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %system%\cmd.exe /c del {malware path and file name}.exe.exe.exe nul
  • %Program Files%\java.exe
  • %System%\svchost.exe -k WerSvcGroup
  • %System%\sc.exe start w32time task_started
  • %Program Files%\java.exe Win7
  • %System%\WerFault.exe -u -p 1784 -s 268

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It creates the following folders:

  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_java.exe_{random characters}

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

Autostart Technique

This Backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Java(TM) Platform Sa 8.02
DisplayName = "Oracle Corporation"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Java(TM) Platform Sa 8.02
ImagePath = "%Program Files%\java.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Java(TM) Platform Sa 8.02
Start = "SERVICE_AUTO_START"

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Java(TM) Platform Sa 8.02

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Java(TM) Platform Sa 8.02\MarkTime

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Java(TM) Platform Sa 8.02\Description

Other System Modifications

This Backdoor modifies the following file(s):

  • %System%\LogFiles\Scm\{random characters}

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

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Java(TM) Platform Sa 8.02
MarkTime = "{date of execution}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\Java(TM) Platform Sa 8.02
Description = "Java(TM) Platform SE 8 Oracle Corporation"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\W32Time
Type = "16"

(Note: The default value data of the said registry entry is 20.)

Dropping Routine

This Backdoor drops the following files:

  • %System%\LogFiles\Scm\{random characters}
  • %Windows%\Temp\WER{random characters}.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\WER{random characters}.tmp.hdmp
  • %Windows%\Temp\WER{random characters}.tmp.appcompat.txt
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_java.exe_{random characters}e\WER{random characters}.tmp.appcompat.txt
  • %Windows%\Temp\WER{random characters}.tmp
  • %Windows%\Temp\WER{random characters}.tmp
  • %Windows%\Temp\WER{random characters}.tmp

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

Other Details

This Backdoor connects to the following possibly malicious URL:

  • http://cndns.{BLOCKED}s.org

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.728.08
FIRST VSAPI PATTERN DATE: 19 Oct 2017
VSAPI OPR PATTERN File: 13.729.00
VSAPI OPR PATTERN Date: 20 Oct 2017

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Identify and terminate files detected as BKDR_ZEGOST.SM45

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

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\SYSTEM\CurrentControlSet\Services
    • Java(TM) Platform Sa 8.02
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Java(TM) Platform Sa 8.02
    • MarkTime
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Java(TM) Platform Sa 8.02
    • Description

Step 5

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\SYSTEM\ControlSet001\services\Java(TM) Platform Sa 8.02
    • MarkTime = "{date of execution}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\Java(TM) Platform Sa 8.02
    • Description = "Java(TM) Platform SE 8 Oracle Corporation"

Step 6

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time
    • From: Type = "16"
      To: Type = ""20""

Step 7

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%\LogFiles\Scm\{random characters}
  • %Windows%\Temp\WER{random characters}.tmp.WERInternalMetadata.xml
  • %Windows%\Temp\WER{random characters}.tmp.hdmp
  • %Windows%\Temp\WER{random characters}.tmp.mdmp
  • %Windows%\Temp\WER{random characters}.tmp.appcompat.txt
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_java.exe_{random characters}\WER{random characters}.tmp.appcompat.txt
  • %Windows%\Temp\WER{random characters}.tmp
  • %Windows%\Temp\WER{random characters}.tmp
  • %Windows%\Temp\WER{random characters}.tmp
  • %Windows%\Temp\WER{random characters}.tmp

Step 8

Search and delete this folder

[ 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.
  • %All Users Profile%\Microsoft\Windows\WER\ReportQueue\AppCrash_java.exe_WER{random characters}

Step 9

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZEGOST.SM45. 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 10

Restore deleted/modified files and/or registry entries from backup

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

    • %System%\LogFiles\Scm\0d9b5d92-3a22-486d-a887-3aa21597cf27


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