TROJ_KRYPTIK.DC

October 09, 2012
 Analysis by: Rhena Inocencio
 Modified by: Joseph Obed
 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:

83,456 bytes

File Type:

EXE

Initial Samples Received Date:

12 Jul 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.

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
KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\{random key name}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}9.{BLOCKED}1.214.180
  • {BLOCKED}3.{BLOCKED}2.252.26
  • {BLOCKED}0.{BLOCKED}6.23.100
  • {BLOCKED}6.{BLOCKED}8.12.158
  • {BLOCKED}9.{BLOCKED}4.194.242
  • {BLOCKED}1.{BLOCKED}7.189.212
  • {BLOCKED}1.{BLOCKED}8.5.140
  • {BLOCKED}4.{BLOCKED}4.164.18
  • {BLOCKED}8.{BLOCKED}8.206.179
  • {BLOCKED}2.{BLOCKED}7.253.106
  • {BLOCKED}3.{BLOCKED}3.134.23
  • {BLOCKED}3.{BLOCKED}8.208.55
  • {BLOCKED}5.{BLOCKED}6.179.185
  • {BLOCKED}7.{BLOCKED}0.41.155
  • {BLOCKED}4.{BLOCKED}3.49.51

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.252.05

FIRST VSAPI PATTERN DATE:

12 Jul 2012

VSAPI OPR PATTERN File:

9.253.00

VSAPI OPR PATTERN Date:

13 Jul 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
    • KB{random number}.exe = "%User Profile%\Application Data\KB{random number}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = "0"

Step 4

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\Windows NT
    • {random key name}

Step 5

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


Did this description help? Tell us how we did.