TROJ_KULUOZ.KN

July 08, 2013
 Analysis by: Adrian Cofreros
 ALIASES:

TrojanDownloader:Win32/Kuluoz.B(Microsoft),Trojan.Win32.Generic.pak!cobra(Sunbelt),TR/Crypt.ZPACK.Gen(Antivir)

 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:

28,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Jul 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 drops a copy of itself in the following folders using different file names:

  • %Application Data%\{random file name}.exe

(Note: %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.)

It leaves the following text files:

  • {malware path}\{malware file name}.txt

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} = "%Application Data%\{random file name}.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{random key 1}

HKEY_CURRENT_USER\Software\{random key 2}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\{random key 1}
{random 1} = "{hex values 1}"

HKEY_CURRENT_USER\Software\{random key 2}
{random 2} = "{hex values 2}"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.186.184:8080
  • http://{BLOCKED}.{BLOCKED}.208.180:8080
  • http://{BLOCKED}.{BLOCKED}.91.224:8080
  • http://{BLOCKED}.{BLOCKED}.224.62:8080
  • http://{BLOCKED}.{BLOCKED}.42.27:8080

It deletes itself after execution.