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Ransom_CERBER.DLFE

October 06, 2016
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan 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:

630,375 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

06 Oct 2016

Arrival Details

This Trojan 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 Trojan creates the following folders:

  • %User Profile%\Microsoft\Speech
  • %User Profile%\Speech\Files
  • %User Profile%\Files\UserLexicons

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other System Modifications

This Trojan modifies the following file(s):

  • %System%\WBEM\AutoRecover\88744D2A29102FC88ECF505DD2E984FC.mof

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

It deletes the following files:

  • %User Temp%\tmp19.tmp

(Note: %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.)

It adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Speech\Voices

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Speech\PhoneConverters

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Speech\CurrentUserLexicon

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon\AppLexicons

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon\{C9E37C15-DF92-4727-85D6-72E5EEB6995A}

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon\{C9E37C15-DF92-4727-85D6-72E5EEB6995A}\
Files

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Speech\AppLexicons

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Speech\AudioOutput

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Wbem\WMIC

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Wbem\WMIC

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Speech\Voices
DefaultTokenId = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Speech\Voices\Tokens\MSSam"

HKEY_CURRENT_USER\Software\Microsoft\
Speech\PhoneConverters
DefaultTokenId = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Speech\PhoneConverters\Tokens\English"

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon
CLSID = "{C9E37C15-DF92-4727-85D6-72E5EEB6995A}"

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon
FlushRate = "10"

HKEY_CURRENT_USER\Software\Microsoft\
Speech\CurrentUserLexicon\{C9E37C15-DF92-4727-85D6-72E5EEB6995A}\
Files
Datafile = "%1a%\Microsoft\Speech\Files\UserLexicons\SP_C9FF76BAD759428787D1E1C964D8F98C.dat"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WMIC
mofcompstatus = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Wbem\WMIC
WMICLC = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Wbem\WMIC
mofcompMUIStatus = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Wbem\WMIC
mofcompMUIStatus = "ffffffff"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WMIC
Cli.mof = "127360152460000000"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WMIC
CliEgAliases.mof = "127360152460000000"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WMIC
CliEgAliases.mfl = "127360152460000000"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\WMIC
mofcompstatus = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Wbem\WMIC
WMICLC = "49"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\CIMOM
Autorecover MOFs timestamp = "131193555426406250"

(Note: The default value data of the said registry entry is 129689362348742500.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\CIMOM
Autorecover MOFs = "{random characters}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\CIMOM
Autorecover MOFs timestamp = "131193555979062500"

(Note: The default value data of the said registry entry is 129689362348742500.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\CIMOM
Autorecover MOFs timestamp = "131193555989843750"

(Note: The default value data of the said registry entry is 129689362348742500.)

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Templates\# HELP DECRYPT #.html
  • %User Profile%\Templates\# HELP DECRYPT #.txt
  • %User Profile%\Templates\# HELP DECRYPT #.url
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.html
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.txt
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.url
  • %User Profile%\Sample Music\# HELP DECRYPT #.html
  • %User Profile%\Sample Music\# HELP DECRYPT #.txt
  • %User Profile%\Sample Music\# HELP DECRYPT #.url
  • %User Profile%\Cookies\# HELP DECRYPT #.html
  • %User Profile%\Cookies\# HELP DECRYPT #.txt
  • %User Profile%\Cookies\# HELP DECRYPT #.url
  • %User Temp%\tmp19.bmp
  • %Desktop%\# HELP DECRYPT #.html
  • %Desktop%\# HELP DECRYPT #.txt
  • %Desktop%\# HELP DECRYPT #.url
  • %User Profile%\UserLexicons\SP_C9FF76BAD759428787D1E1C964D8F98C.dat
  • %User Temp%\tmp1.tmp
  • %User Temp%\tmp5.tmp
  • %System%\WBEM\AutoRecover\C8463ECBE33BC240263A0B094E46D510.mof
  • %User Temp%\tmp9.tmp
  • %System%\WBEM\AutoRecover\23BDE61F1F4FACE17E9B0C01F2A1FD9B.mof

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}0.1

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.8

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\Speech
    • Voices
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech
    • PhoneConverters
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech
    • CurrentUserLexicon
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon
    • AppLexicons
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon
    • {C9E37C15-DF92-4727-85D6-72E5EEB6995A}
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon\{C9E37C15-DF92-4727-85D6-72E5EEB6995A}
    • Files
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech
    • AppLexicons
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Speech
    • AudioOutput
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Wbem\
    • WMIC
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Wbem\
    • WMIC

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\Speech\Voices
    • DefaultTokenId = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Speech\Voices\Tokens\MSSam"
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\PhoneConverters
    • DefaultTokenId = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Speech\PhoneConverters\Tokens\English"
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon
    • CLSID = "{C9E37C15-DF92-4727-85D6-72E5EEB6995A}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon
    • FlushRate = "10"
  • In HKEY_CURRENT_USER\Software\Microsoft\Speech\CurrentUserLexicon\{C9E37C15-DF92-4727-85D6-72E5EEB6995A}\Files
    • Datafile = "%1a%\Microsoft\Speech\Files\UserLexicons\SP_C9FF76BAD759428787D1E1C964D8F98C.dat"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WMIC
    • mofcompstatus = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Wbem\WMIC
    • WMICLC = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Wbem\WMIC
    • mofcompMUIStatus = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Wbem\WMIC
    • mofcompMUIStatus = "ffffffff"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WMIC
    • Cli.mof = "127360152460000000"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WMIC
    • CliEgAliases.mof = "127360152460000000"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WMIC
    • CliEgAliases.mfl = "127360152460000000"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WMIC
    • mofcompstatus = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Wbem\WMIC
    • WMICLC = "49"

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_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM
    • From: Autorecover MOFs timestamp = "131193555426406250"
      To: Autorecover MOFs timestamp = ""129689362348742500""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM
    • From: Autorecover MOFs = "{random characters}"
      To: Autorecover MOFs = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM
    • From: Autorecover MOFs timestamp = "131193555979062500"
      To: Autorecover MOFs timestamp = ""129689362348742500""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM
    • From: Autorecover MOFs timestamp = "131193555989843750"
      To: Autorecover MOFs timestamp = ""129689362348742500""

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.
  • %User Profile%\Templates\# HELP DECRYPT #.html
  • %User Profile%\Templates\# HELP DECRYPT #.txt
  • %User Profile%\Templates\# HELP DECRYPT #.url
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.html
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.txt
  • %User Profile%\Sample Pictures\# HELP DECRYPT #.url
  • %User Profile%\Sample Music\# HELP DECRYPT #.html
  • %User Profile%\Sample Music\# HELP DECRYPT #.txt
  • %User Profile%\Sample Music\# HELP DECRYPT #.url
  • %User Profile%\Cookies\# HELP DECRYPT #.html
  • %User Profile%\Cookies\# HELP DECRYPT #.txt
  • %User Profile%\Cookies\# HELP DECRYPT #.url
  • %User Temp%\tmp19.bmp
  • %Desktop%\# HELP DECRYPT #.html
  • %Desktop%\# HELP DECRYPT #.txt
  • %Desktop%\# HELP DECRYPT #.url
  • %User Profile%\UserLexicons\SP_C9FF76BAD759428787D1E1C964D8F98C.dat
  • %User Temp%\tmp1.tmp
  • %User Temp%\tmp5.tmp
  • %System%\WBEM\AutoRecover\C8463ECBE33BC240263A0B094E46D510.mof
  • %User Temp%\tmp9.tmp
  • %System%\WBEM\AutoRecover\23BDE61F1F4FACE17E9B0C01F2A1FD9B.mof

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.
  • %User Profile%\Microsoft\Speech
  • %User Profile%\Speech\Files
  • %User Profile%\Files\UserLexicons

Step 7

Scan your computer with your Trend Micro product to delete files detected as Ransom_CERBER.DLFE. 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 8

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%\WBEM\AutoRecover\88744D2A29102FC88ECF505DD2E984FC.mof

Step 9

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.

  • %User Temp%\tmp19.tmp


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