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TROJ_KRYPTIK.SMP

April 25, 2013
 ALIASES:

PWS:Win32/Zbot.gen!AK (Microsoft); Trojan-Spy.Win32.Zbot.guoj (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

 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:

312,320 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Dec 2012

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\Moec

(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
{C8B0FB29-AD41-AD40-5C09-405F58D6634D} = "%User Profile%\Moec\ydsaf.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Efsy

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts\Active Directory GC

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts\Bigfoot

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts\Active Directory GC
LDAP Server ID = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Account Manager\Accounts\Bigfoot
LDAP Server ID = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Efsy
2727f138 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Efsy
22468gii = "9b55c88a"

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
28561:UDP = "28561:UDP:*:Enabled:UDP 28561"

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

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
16140:TCP = "16140:TCP:*:Enabled:TCP 16140"

HKEY_CURRENT_USER\Software\Microsoft\
Efsy
5be5cf2 = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Efsy
22468gii = "{random values}"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\Moec
  • %User Profile%\Moec\ydsaf.exe
  • %Application Data%\aqjun.qia

(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.. %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\Microsoft
    • Efsy
  • In HKEY_CURRENT_USER\Software\Microsoft
    • Internet Account Manager
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager
    • Accounts
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts
    • Active Directory GC
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts
    • Bigfoot

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
    • {C8B0FB29-AD41-AD40-5C09-405F58D6634D} = "%User Profile%\Moec\ydsaf.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts\Active Directory GC
    • LDAP Server ID = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Account Manager\Accounts\Bigfoot
    • LDAP Server ID = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Efsy
    • 2727f138 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Efsy
    • 22468gii = "9b55c88a"
  • 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
    • 28561:UDP = "28561:UDP:*:Enabled:UDP 28561"
  • 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
    • 16140:TCP = "16140:TCP:*:Enabled:TCP 16140"
  • In HKEY_CURRENT_USER\Software\Microsoft\Efsy
    • 5be5cf2 = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Efsy
    • 22468gii = "{random values}"

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%\Application Data\Moec
  • %User Profile%\Moec\ydsaf.exe
  • %Application Data%\aqjun.qia

Step 6

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\Moec

Step 7

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