TROJ_DLOAD.AZC
Trojan.Win32.Jorik.Geral.per (Kaspersky); May be infected by unknown virus Win32/DH{AwknD1hnNgo} (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
49,664 bytes
EXE
Yes
08 Apr 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 drops the following copies of itself into the affected system:
- %Program Files%\dxv.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%\Common Files\Plugins
(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 registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Avt-Net\Parameters
Other System Modifications
This Trojan deletes the following files:
- %Program Files%\syslass.cpl
- %Program Files%\Common Files\Plugins\!DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01//EN http://www.w3.org/TR/html4/strict.exe
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
Avt-Net = "Avt-Net"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
Description = "{random characters}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
DisplayName = "Portable Sound Serial Number Services"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
Group = "Com Infrastructure"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
FailureAction = "{random values}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net
ImagePath = "%SystemRoot%\system32\svchost -k Avt-Net"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Avt-Net\Parameters
ServiceDll = "%SystemRoot%\system32\svcnet32.dll"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
NeverShowExt = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
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 2.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0x00000001 (1)"
(Note: The default value data of the said registry entry is 1.)
Dropping Routine
This Trojan drops the following files:
- %System%\svcnet32.dll
- %Program Files%\Common Files\Plugins\rouji.txt
- %Program Files%\Common Files\Plugins\!DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01//EN http://www.w3.org/TR/html4/strict.dtd
- %Program Files%\syslass.cpl
Other Details
This Trojan connects to the following possibly malicious URL:
- http://www.{BLOCKED}g.info/rouji.txt
- http://www.{BLOCKED}g.info/{random path}
This report is generated via an automated analysis system.
SOLUTION
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
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\SYSTEM\CurrentControlSet\Services\Avt-Net
- Parameters
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 NT\CurrentVersion\SvcHost
- Avt-Net = "Avt-Net"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- Description = "{random characters}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- DisplayName = "Portable Sound Serial Number Services"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- Group = "Com Infrastructure"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- ObjectName = "LocalSystem"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- Start = "2"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- Type = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- FailureAction = "{random values}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net
- ImagePath = "%SystemRoot%\system32\svchost -k Avt-Net"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Avt-Net\Parameters
- ServiceDll = "%SystemRoot%\system32\svcnet32.dll"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
- NeverShowExt = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out 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 = ""2""
- From: Hidden = "2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
- From: CheckedValue = "0x00000001 (1)"
To: CheckedValue = ""1""
- From: CheckedValue = "0x00000001 (1)"
Step 6
Search and delete these components
- %System%\svcnet32.dll
- %Program Files%\Common Files\Plugins\rouji.txt
- %Program Files%\Common Files\Plugins\!DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01//EN http://www.w3.org/TR/html4/strict.dtd
- %Program Files%\syslass.cpl
Step 7
Search and delete this folder
- %Program Files%\Common Files\Plugins
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOAD.AZC. 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 9
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Program Files%\syslass.cpl
- %Program Files%\Common Files\Plugins\!DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01//EN http://www.w3.org/TR/html4/strict.exe
Did this description help? Tell us how we did.