ALIASES:

Trojan:Win32/Agent.OQ (Microsoft); W32/HLLP.Philis.gen (McAfee); Backdoor.Trojan (Symantec); PAK:PEPatch, Backdoor.Win32.Delf.izv (Kaspersky); Packed.Win32.MaskPE (v) (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 168,448 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 13 Apr 2012

Arrival Details

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

  • %Favorites%\netservice.exe

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

It creates the following folders:

  • %Favorites%\plugin

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

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Setup
netinfo = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Setup
cover = "795647"

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

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\Windows\CurrentVersion\Setup
    • netinfo = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup
    • cover = "795647"

Step 3

Search and delete this folder

[ 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.
  • %Favorites%\plugin

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR_DELF.MYJ. 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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