Modified by: Kathleen Notario
ALIASES:

TrojanDownloader:Win32/Renos.KF (Microsoft); Downloader-BWS (McAfee); Trojan.FakeAV!gen11 (Symantec); Packed.Win32.Krap.ag (Kaspersky); Trojan.Win32.FraudPack.gen (v) (Sunbelt); Trojan-Downloader:W32/Renos.gen!W (FSecure)

 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.

  TECHNICAL DETAILS

File Size: 211,456 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 15 Mar 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.

Installation

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

  • {malware path and file name}.exe
  • %Windows%\msa.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\4VDD85L8NF

It adds the following registry entries:

HKEY_CURRENT_USER\Software\4VDD85L8NF
Pq6 = "0"

HKEY_CURRENT_USER\Software\4VDD85L8NF
Pq14 = "0"

HKEY_CURRENT_USER\Software\4VDD85L8NF
Pq0 = "1cd333"

HKEY_CURRENT_USER\Software\4VDD85L8NF
Pq1 = "6efcf76"

Dropping Routine

This Trojan drops the following files:

  • %Windows%\Tasks\{35DC3473-A719-4d14-B7C1-FD326CA84A0C}.job

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

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 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
    • 4VDD85L8NF

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\4VDD85L8NF
    • Pq6 = "0"
  • In HKEY_CURRENT_USER\Software\4VDD85L8NF
    • Pq14 = "0"
  • In HKEY_CURRENT_USER\Software\4VDD85L8NF
    • Pq0 = "1cd333"
  • In HKEY_CURRENT_USER\Software\4VDD85L8NF
    • Pq1 = "6efcf76"

Step 4

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %Windows%\Tasks\{35DC3473-A719-4d14-B7C1-FD326CA84A0C}.job

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.BLR. 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.