Ransom_CERBER.VSAFX

March 01, 2017
 ALIASES:

Ransom:Win32/Cerber (Microsoft); Ransomware-FMJ!B8AAA5ABE043 (McAfee); Packed.Generic.493 (Symantec); HEUR:Trojan.Win32.Generic (Kaspersky); Mal/Elenoocka-E (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Crypt7.GKK (AVG)

 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:

229,648 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 Mar 2017

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 Temp%\6abce574
  • %User Profile%\Microsoft\Speech
  • %User Profile%\Speech\Files
  • %User Profile%\Files\UserLexicons

(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.. %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 deletes the following files:

  • %User Temp%\tmp6.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

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_1EB1410746D44F83B941FA72B10517AB.dat"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\6abce574\42c5.tmp
  • %User Temp%\6abce574\4afc.tmp
  • %User Profile%\cookies\_HELP_HELP_HELP_6Y0J_.hta
  • %User Profile%\cookies\_HELP_HELP_HELP_KNSLA5_.png
  • %User Temp%\tmp6.bmp
  • %Desktop%\_HELP_HELP_HELP_KC8Z5_.hta
  • %Desktop%\_HELP_HELP_HELP_IONL0_.png
  • %User Profile%\UserLexicons\SP_1EB1410746D44F83B941FA72B10517AB.dat

(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.. %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.. %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.)

Other Details

This Trojan 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

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_1EB1410746D44F83B941FA72B10517AB.dat"

Step 4

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 Temp%\6abce574\42c5.tmp
  • %User Temp%\6abce574\4afc.tmp
  • %User Profile%\cookies\_HELP_HELP_HELP_6Y0J_.hta
  • %User Profile%\cookies\_HELP_HELP_HELP_KNSLA5_.png
  • %User Temp%\tmp6.bmp
  • %Desktop%\_HELP_HELP_HELP_KC8Z5_.hta
  • %Desktop%\_HELP_HELP_HELP_IONL0_.png
  • %User Profile%\UserLexicons\SP_1EB1410746D44F83B941FA72B10517AB.dat

Step 5

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 Temp%\6abce574
  • %User Profile%\Microsoft\Speech
  • %User Profile%\Speech\Files
  • %User Profile%\Files\UserLexicons

Step 6

Scan your computer with your Trend Micro product to delete files detected as Ransom_CERBER.VSAFX. 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 7

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%\tmp6.tmp


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