Modified by: Jimelle Monteser
ALIASES:

VirTool:Win32/Obfuscator.XQ (Microsoft); ZeroAccess.hr (McAfee); Trojan.Win32.Generic!BT (Sunbelt); Gen:Variant.Kazy.129145 (FSecure); Trojan horse Generic_s.ACB (AVG)

 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:
 INFORMATION EXPOSURE:

  • 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 the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 171,008 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 26 Jan 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 creates the following folders:

  • %System Root%\RECYCLER
  • %System Root%\RECYCLER\{random 1}
  • %System Root%\RECYCLER\{random 1}\{random 2}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 1}

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 1}\InprocServer32

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 1}
ThreadingModel = "Both"

HKEY_CURRENT_USER\Software\Classes\
CLSID\{GUID 1}
Default = "%System Root%\RECYCLER\{random}\{random}\n"

It modifies the following registry entries:

HKEY_CLASSES_ROOT\CLSID\{GUID 1}\
InprocServer32
Default = "System Root%\RECYCLER\{random}\{random}\n"

(Note: The default value data of the said registry entry is "{numeric values}".)

HKEY_CLASSES_ROOT\CLSID\{GUID 1}\
InprocServer32
ThreadingModel = "Both"

(Note: The default value data of the said registry entry is "Apartment".)

HKEY_CLASSES_ROOT\CLSID\{GUID 2}\
InprocServer32
Default = "System Root%\RECYCLER\{random}\{random}\n"

(Note: The default value data of the said registry entry is "%Windows%\wbem\fastprox.dll".)

HKEY_LOCAL_MACHINE\CLSID\{GUID 2}\
InprocServer32
Default = "System Root%\RECYCLER\{random}\{random}\n"

(Note: The default value data of the said registry entry is "%Windows%\wbem\fastprox.dll".)

Dropping Routine

This Trojan drops the following files:

  • %System Root%\RECYCLER\{random 1}\{random 2 }\@
  • %System Root%\RECYCLER\{random 1}\{random 2}\n

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://j.{BLOCKED}d.com/app/geoip.js

It deletes the initially executed copy of itself

  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

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\Classes\CLSID
    • {GUID 1}
  • In HKEY_CURRENT_USER\Software\Classes\CLSID\{GUID 1}
    • InprocServer32

Step 3

Restore this modified 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_CLASSES_ROOT\CLSID\{GUID 1}\InprocServer32
    • From: Default = "System Root%\RECYCLER\{random}\{random}\n"
      To: Default = "{numeric values}"
  • In HKEY_CLASSES_ROOT\CLSID\{GUID 1}\InprocServer32
    • From: ThreadingModel = "Both"
      To: ThreadingModel = "Apartment"
  • In HKEY_CLASSES_ROOT\CLSID\{GUID 2}\InprocServer32
    • From: Default = "System Root%\RECYCLER\{random}\{random}\n"
      To: Default = "%Windows%\wbem\fastprox.dll"
  • In HKEY_LOCAL_MACHINE\CLSID\{GUID 2}\InprocServer32
    • From: Default = "System Root%\RECYCLER\{random}\{random}\n"
      To: Default = "%Windows%\wbem\fastprox.dll"

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.
  • %System Root%\RECYCLER

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_SIREFEF.SM9. 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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