TROJ_KRYPTIK.LVZ

October 09, 2012
 Analysis by: Sabrina Lei Sioting
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Trojan is injected into all running processes to remain memory resident.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size:

304,608 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

17 May 2012

Payload:

Downloads files

Arrival Details

This Trojan may be downloaded from the following remote sites:

  • http://{BLOCKED}merzeuger.com/bFdp8Wh.exe
  • http://{BLOCKED}oup.com/5g51T.exe
  • http://{BLOCKED}.co.cc/Sbw5cQw.exe

Installation

This Trojan drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\{random1}\{random}.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It drops the following files:

  • %User Profile%\Application Data\{random2}\{random}.{random}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %User Profile%\Application Data\{random1}
  • %User Profile%\Application Data\{random2}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It is injected into all running processes to remain memory resident.

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
{random CLSID} = "%User Profile%\Application Data\{random1}\{random}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random}

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

NOTES:

This Trojan connects using varying UDP ports to possibly download its configuration file. The configuration file may contain URLs where it downloads an updated copy of itself and where it sends its gathered information. It may also contain URLs of its target online banking and finance-related sites from where it steals the information.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.118.03

FIRST VSAPI PATTERN DATE:

17 May 2012

VSAPI OPR PATTERN File:

9.119.00

VSAPI OPR PATTERN Date:

18 May 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

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\Windows\CurrentVersion\Run
    • {Random CLSID} = "%User Profile%\Application Data\{random1}.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"

Step 4

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 Profile%\Application Data\{random1}
  • %User Profile%\Application Data\{random2}

Step 5

Reset Internet security settings

[ Learn More ]

Step 6

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

NOTES:

Note:

The created registry key HKEY_CURRENT_USER\Software\Microsoft\{random} cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup if the users have one. Note that the key need not to be deleted since it won't cause the user system any harm.


Did this description help? Tell us how we did.

Related Malware