BKDR_AGENT.AXNN
Trojan:Win32/Sisproc, Trojan:Win32/SystemHijack.gen!C, VirTool:Win32/Obfuscator.XZ, VirTool:Win32/Ob (Microsoft); PWS-Mmorpg!b2d (McAfee); Trojan.Gen (Symantec); Trojan.Win32.Generic!BT (Sunbelt); MemScan:Trojan.Generic.4262080 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
It deletes itself after execution.
TECHNICAL DETAILS
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.
Autostart Technique
This backdoor 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\Wida\Parameters
Other System Modifications
This backdoor adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Wida
Description = "Securely enables the AutoConfig,management, and disclosure of digital identities."
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Wida\Parameters
ServiceDll = "%System%\prncav.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ShareManConn
Description = "Windows Help System for X32 windows desktop"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{random characters}"
(Note: The default value data of the said registry entry is {random values}.)
Dropping Routine
This backdoor drops the following files:
- %User Temp%\39250.exe
- %User Temp%\41125.exe
- %System%\prncav.dll
- %System%\WinConn32.exe
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://43453.{BLOCKED}0.info:1400/google/0701.txt
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
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
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\Wida
- 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\SYSTEM\ControlSet001\Services\Wida
- Description = "Securely enables the AutoConfig,management, and disclosure of digital identities."
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Wida\Parameters
- ServiceDll = "%System%\prncav.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ShareManConn
- Description = "Windows Help System for X32 windows desktop"
Step 5
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- From: netsvcs = "{random characters}"
To: netsvcs = ""{random values}""
- From: netsvcs = "{random characters}"
Step 6
Search and delete these files
- %User Temp%\39250.exe
- %User Temp%\41125.exe
- %System%\prncav.dll
- %System%\WinConn32.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_AGENT.AXNN. 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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