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RANSOM_CYPHERKEY.A

July 06, 2016
 Modified by: Jennifer Gumban
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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 connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

165,681 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 Jul 2016

Payload:

Connects to URLs/IPs, Encrypts files

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.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Wbem\WMIC

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Wbem\WMIC

It adds the following registry entries:

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 = "131097917045000000"

(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 = "131097917536093750"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM\CIMOM
Autorecover MOFs timestamp = "131097917546250000"

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

Other Details

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

  • {BLOCKED}.{BLOCKED}.72.45
  • http://{BLOCKED}ravlja.net/media/7.php?a={id}:{os}:{value}:{value}:{version}:{value}

It encrypts files with the following extensions:

  • .aif
  • .aifc
  • .aiff
  • .asf
  • .asx
  • .au
  • .bas
  • .bat
  • .bmp
  • .cmd
  • .com
  • .cpl
  • .dib
  • .doc
  • .docx
  • .dot
  • .dvr-ms
  • .emf
  • .exe
  • .gif
  • .hta
  • .htm
  • .html
  • .ico
  • .IVF
  • .jfif
  • .jpe
  • .jpeg
  • .jpg
  • .lnk
  • .m1v
  • .m3u
  • .mht
  • .mid
  • .midi
  • .mp2
  • .mp2v
  • .mp3
  • .mpa
  • .mpe
  • .mpeg
  • .mpg
  • .mpv2
  • .msi
  • .pdf
  • .pif
  • .png
  • .pot
  • .pps
  • .ppt
  • .pptx
  • .reg
  • .rle
  • .rmi
  • .rtf
  • .scr
  • .search-ms
  • .snd
  • .tif
  • .tiff
  • .vb
  • .wav
  • .wax
  • .wm
  • .wma
  • .wmf
  • .wmv
  • .wmx
  • .wvx
  • .xbap
  • .xls
  • .xlsx
  • .xlt
  • .xlw
  • .xml
  • .xps
  • .zip

It drops the following file(s)/component(s):

  • {folders containing encrypted files}\CYPHER.KEY7
  • {folders containing encrypted files}\INSTRUCTIONS-README7.TXT
  • %User Profile%\My Documents\{id}.log - encrypted files

(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.)

It does the following:

  • It deletes shadow copies by executing the following command:
    %System%\wbem\WMIC.exe" shadowcopy delete

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

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.574.07

FIRST VSAPI PATTERN DATE:

07 Jun 2016

VSAPI OPR PATTERN File:

12.575.00

VSAPI OPR PATTERN Date:

08 Jun 2016

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_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_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 = "131097917045000000"
      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 = "131097917536093750"
      To: Autorecover MOFs timestamp = ""129689362348742500""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM
    • From: Autorecover MOFs timestamp = "131097917546250000"
      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.
  • CYPHER.KEY7
  • INSTRUCTIONS-README7.TXT

Step 6

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

Restore encrypted files from backup.


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