TROJ_PACKED.AYW
Mal/EncPk-EK ( Sophos); Trojan.Packed.NsAnti (Symantex); TrojanDownloader:Win32/Frethog.C (Microsoft)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Trojan may be dropped by other malware.
It requires its main component to successfully perform its intended routine.
TECHNICAL DETAILS
Arrival Details
This Trojan may be dropped by other malware.
Installation
This Trojan is injected into the following processes running in memory:
- Explorer.exe
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\CLSID\MADOWN
It adds the following registry entries:
HKEY_CLASSES_ROOT\CLSID\MADOWN
urlinfo = "{random characters}"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"
(Note: The default value data of the said registry entry is 1.)
Download Routine
This Trojan connects to the following Web site(s) to download and execute a malicious file:
- http://www.{BLOCKED}w.com/rbv/uu.rar
Other Details
This Trojan requires its main component to successfully perform its intended routine.
SOLUTION
Step 1
For Windows ME and XP 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
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
- MADOWN
- MADOWN
Step 3
Restore this modified registry value
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\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From Hidden = 2
To: Hidden = 1
- From Hidden = 2
- From: ShowSuperHidden = 0
To: ShowSuperHidden = 1
- From: CheckedValue = 0
To: CheckedValue = 1
Step 4
Scan your computer with your Trend Micro product to delete files detected as TROJ_PACKED.AYW 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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