TROJ_DYFUCA.BE
Adware-DFC. (McAfee); Adware.NetOptimizer (Symantec); Trojan-Downloader.Win32.Dyfuca.ak (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan horse Downloader.Dyfica.AJ (AVG)
Windows 2000, Windows XP, Windows Server 2003
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
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:
- %Program Files%\Internet Optimizer\optimize.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
It creates the following folders:
- %Program Files%\Internet Optimizer
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Internet Optimizer = "%Program Files%\Internet Optimizer\optimize.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
DyFuCA
HKEY_LOCAL_MACHINE\Software\Avenue Media
HKEY_CURRENT_USER\Software\Avenue Media
HKEY_LOCAL_MACHINE\Software\Avenue Media\
Internet Optimizer
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
DisplayIcon = "%Program Files%\Internet Optimizer\optimize.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
UninstallString = "%Program Files%\Internet Optimizer\optimize.exe /u 2"
HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
CLS = "wsi14"
HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
RID = "r01"
HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
Version = "2.2.5"
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DyFuCA Active Alert
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DyFuCA Software Installer
Other Details
This Trojan connects to the following possibly malicious URL:
- http://www.{BLOCKED}et-optimizer.com/conf/signin/?{random characters}
This report is generated via an automated analysis system.
SOLUTION
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
Restart in Safe Mode
Step 3
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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
- Internet Optimizer
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
- DyFuCA
- In HKEY_LOCAL_MACHINE\Software
- Avenue Media
- In HKEY_CURRENT_USER\Software
- Avenue Media
- In HKEY_LOCAL_MACHINE\Software\Avenue Media
- Internet Optimizer
Step 4
Delete this 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- Internet Optimizer = "%Program Files%\Internet Optimizer\optimize.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Internet Optimizer
- DisplayIcon = "%Program Files%\Internet Optimizer\optimize.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Internet Optimizer
- UninstallString = "%Program Files%\Internet Optimizer\optimize.exe /u 2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
- CLS = "wsi14"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
- RID = "r01"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
- Version = "2.2.5"
Step 5
Search and delete this folder
- %Program Files%\Internet Optimizer
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DYFUCA.BE. 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.
Step 7
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
- DyFuCA Active Alert
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
- DyFuCA Software Installer
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