RANSOM_CRYPNISCA.A

 Analysis by: Sammy Chua

 ALIASES:

Ransom:Win32/Denisca!rfn (Microsoft); Ransom.Denisca.S4 (CAT-QuickHeal); Trojan/Win32.Ransom (AhnLab-V3);

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet

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 does not have any propagation routine.

It does not have any backdoor routine.

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible. It deletes the initially executed copy of itself. It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size:

35,328 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Nov 2015

Payload:

Connects to URLs/IPs

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 adds the following folders:

  • %Application Data%\ChromeUpdServeis

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 drops the following copies of itself into the affected system:

  • %Application Data%\ChromeUpdServeis\Microsoft_{10 letters}.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 processes:

  • svchost.exe

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • sc0rpi0n_for_ever_2_10141105

It injects codes into the following process(es):

  • created svchost.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ChromeUpdServeisSystem = "%Application Data%\ChromeUpdServeis\Microsoft_{10 letters}.exe"

Other System Modifications

This Trojan deletes the following files:

  • %Application Data%\ChromeUpdServeis\Microsoft_{10 letters}.exe:Zone.Identifier
  • %Application Data%\transend.sys
  • %Application Data%\$PIGNW234CW6Y2H.sys

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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\
Internet Explorer\MINIE

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ChromeUpdServeisName = "Microsoft_{10 letters}.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ChromeUpdServeis32 = "{malware file path}\{malware file name}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableFirstRunCustomize = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Play_Background_Sounds = "no"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\MINIE
ShowStatusBar = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
StatusBarWeb = "1"

(Note: The default value data of the said registry entry is "0".)

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan saves the files it downloads using the following names:

  • %Application Data%\$EB42FEABC.sys
  • %Application Data%\$FFFCB712AC.sys
  • %Application Data%\NUF3$F@UHT.sys

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

Other Details

This Trojan connects to the following website to send and receive information:

  • {BLOCKED}.{BLOCKED}.187.106
  • {BLOCKED}.{BLOCKED}.187.107

However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself

It gathers the following information and reports it to its servers:

  • Volume Serial Number (only one from "C:\" to "H:\", which ever comes first)
  • Hash of the dropped copy of the malware
  • OS Version
  • Internet Explorer Version

NOTES:

It connects to the URL https://twitter.com/search?q={serial}{hash from serveisname}&src=typd&vertical=default&f=tweets

It executes the following command to open a hidden browser:

%Program Files%\Google\Chrome\Application\chrome.exe --multi-profiles --disable-translate --disable-infobars --no-message-box --mute-audio --user-data-dir=""%Application Data%\Google\Chrome\default2" http://{blocked}105

  SOLUTION

Minimum Scan Engine:

9.800

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • ChromeUpdServeisSystem = "%Application Data%\ChromeUpdServeis\Microsoft_{10 letters}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • ChromeUpdServeisName = "Microsoft_{10 letters}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • ChromeUpdServeis32 = "{malware file path}\{malware file name}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • DisableFirstRunCustomize = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Play_Background_Sounds = "no"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\MINIE
    • ShowStatusBar = "1"

Step 5

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\Internet Explorer
    • MINIE

Step 6

Restore this modified 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\Internet Explorer\Main
    • From: StatusBarWeb = "1"
      To: StatusBarWeb = "0"

Step 7

Search and delete these files

[ 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.
  • %Application Data%\$EB42FEABC.sys
  • %Application Data%\$FFFCB712AC.sys
  • %Application Data%\NUF3$F@UHT.sys

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.
  • %Application Data%\ChromeUpdServeis

Step 9

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

Step 10

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