TROJ_KRYPTIK.OYV

January 28, 2013
 ALIASES:

PWS:Win32/Fareit (Microsoft); Trojan-PSW.Win32.Tepfer.ekul (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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:

112,128 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Jan 2013

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%\Application Data\Paraen

(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.)

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
{58C4EBA0-47A8-AD40-8C85-A85A94978B48} = "%User Profile%\Paraen\wupa.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR
HWID = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
Client Hash = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
48CD89827939B3A8976D9BB0993BC338 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager
Server ID = "4"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
FirstRun = "1"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkContactRefresh = "0"

HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkFolderRefresh = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg
3186edab = "63ffaf65"

HKEY_CURRENT_USER\Software\WinRAR
76D357AF5C62AA12CC9CE93B4FF550AA = "{random values}"

HKEY_CURRENT_USER\Software\WinRAR
927CA7FD8C0A90718E96621ABD8615B2 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg
35584e59 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg
3186edab = "JK//Yw==?"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
18550:UDP = "18550:UDP:*:Enabled:UDP 18550"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
19270:TCP = "19270:TCP:*:Enabled:TCP 19270"

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg
14d1ig5j = "Quf/YxT7g2NC10tI?_CHAR(0x05)_lF?r?rame"

HKEY_CURRENT_USER\Software\Microsoft\
Ojdaeg
3186edab = "{random values}"

It modifies the following registry entries:

HKEY_CURRENT_USER\Identities
Last Username = "Main Identity"

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

HKEY_CURRENT_USER\Identities
Last User ID = "{341F68BA-C841-4200-A7B4-3D5CFF202166}"

(Note: The default value data of the said registry entry is {C0FE0177-5693-4537-9331-A7402AD82D40}.)

HKEY_CURRENT_USER\Identities
Identity Login = "9853"

(Note: The default value data of the said registry entry is 98053.)

HKEY_CURRENT_USER\Identities
Identity Ordinal = "2"

(Note: The default value data of the said registry entry is 1.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\64921.exe
  • %User Temp%\75046.exe
  • %User Temp%\79125.exe
  • %User Profile%\Application Data\Paraen
  • %User Profile%\Paraen\wupa.exe
  • %Application Data%\omeb.ezo

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

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Restart in Safe Mode

[ Learn More ]

Step 3

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
    • WinRAR
  • In HKEY_CURRENT_USER\Software\Microsoft
    • Ojdaeg

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
    • {58C4EBA0-47A8-AD40-8C85-A85A94978B48} = "%User Profile%\Paraen\wupa.exe"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • HWID = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • Client Hash = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • 48CD89827939B3A8976D9BB0993BC338 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager
    • Server ID = "4"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • FirstRun = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • OlkContactRefresh = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4
    • OlkFolderRefresh = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ojdaeg
    • 3186edab = "63ffaf65"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • 76D357AF5C62AA12CC9CE93B4FF550AA = "{random values}"
  • In HKEY_CURRENT_USER\Software\WinRAR
    • 927CA7FD8C0A90718E96621ABD8615B2 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ojdaeg
    • 35584e59 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ojdaeg
    • 3186edab = "JK//Yw==?"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 18550:UDP = "18550:UDP:*:Enabled:UDP 18550"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 19270:TCP = "19270:TCP:*:Enabled:TCP 19270"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ojdaeg
    • 14d1ig5j = "Quf/YxT7g2NC10tI?_CHAR(0x05)_lF?r?rame"
  • In HKEY_CURRENT_USER\Software\Microsoft\Ojdaeg
    • 3186edab = "{random values}"

Step 5

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_CURRENT_USER\Identities
    • From: Last Username = "Main Identity"
      To: Last Username = ""Main Identity""
  • In HKEY_CURRENT_USER\Identities
    • From: Last User ID = "{341F68BA-C841-4200-A7B4-3D5CFF202166}"
      To: Last User ID = ""{C0FE0177-5693-4537-9331-A7402AD82D40}""
  • In HKEY_CURRENT_USER\Identities
    • From: Identity Login = "9853"
      To: Identity Login = ""98053""
  • In HKEY_CURRENT_USER\Identities
    • From: Identity Ordinal = "2"
      To: Identity Ordinal = ""1""

Step 6

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%\64921.exe
  • %User Temp%\75046.exe
  • %User Temp%\79125.exe
  • %User Profile%\Application Data\Paraen
  • %User Profile%\Paraen\wupa.exe
  • %Application Data%\omeb.ezo

Step 7

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.
  • %User Profile%\Application Data\Paraen

Step 8

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