TROJ_KOBLU.AU

March 01, 2013
 Analysis by: Sabrina Lei Sioting
 ALIASES:

Refpron.gen.h (McAfee), Trojan.Win32.Sopiclick.b (Sunbelt), W32/Koblu.A.gen!Eldorado (Authentium), W32/Koblu.BPA!tr (Fortinet), Trojan.Win32.Koblu (Ikarus)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

77,312 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Jan 2010

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.

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
UpdateNew = "{hex values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
WBEM
uid = "unknow"

Backdoor Routine

This Trojan opens the following ports:

  • 8392

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.com
  • {BLOCKED}vity.com
  • {BLOCKED}05.218
  • {BLOCKED}7.154
  • {BLOCKED}1.101

However, as of this writing, the said sites are inaccessible.

NOTES:
It copies the legitimate file %System%\urlmon.dll and saves it as %User Temp%\x1c{numbers}.dll.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

6.766.05

FIRST VSAPI PATTERN DATE:

13 Jan 2010

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

Identify and terminate files detected as TROJ_KOBLU.AU

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
    • UpdateNew = "{hex values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM
    • uid = "unknow"

Step 4

Search and delete the file detected as TROJ_KOBLU.AU

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_KOBLU.AU. 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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