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For remove W32.IRCBot.DCN virus,please clean/delete all W32.IRCBot.DCN infected files and Delete/Modify any values W32.IRCBot.DCN added to the registry as following:
When the worm executes, it creates the following file:
%System%\wbem\rpchost.exe
It then modifies the following file in order to increase the limit for the number of concurrent TCP/IP connections:
%System%\drivers\tcpip.sys
Next, the worm creates the following registry entries so that it executes whenever Windows starts:
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"Generic Host Process for Win32 Service" = "%System%\wbem\rpchost.exe"
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServices\"Generic Host Process for Win32 Service" = "%System%\wbem\rpchost.exe"
It also creates the following registry entries:
- HKEY_CURRENT_USER\Software\Microsoft\OLE\"Generic Host Process for Win32 Service" = "%System%\wbem\rpchost.exe"
- HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Control\Lsa\"Generic Host Process for Win32 Service" = "%System%\wbem\rpchost.exe"
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List\"%System%\wbem\rpchost.exe" = "%System%\wbem\rpchost.exe:*:Enabled:Generic Host Process for Win32 Service"
The worm then connects to the following IRC server:
help.dawnsoul.net:7654
It then opens a back door and allows a remote attacker to gain access to the compromised computer.
It may also download potentially malicious files on to the compromised computer.
The worm spreads through CIFS shares with weak passwords.
It also spreads by exploiting the following vulnerabilities:
- Microsoft SQL Server Web Task Stored Procedure Privilege Escalation Vulnerability (BID 5980)
- Microsoft Windows DCOM RPC Interface Buffer Overrun Vulnerability (BID 8205)
- Microsoft Windows LSASS Buffer Overrun Vulnerability (BID 10108)
RecommendationsSymantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":
- Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
- If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
- Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
- Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
- Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
- Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
- Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
For successful remove W32.IRCBot.DCN virus,you may also need do as following:
1. Temporarily Disable System Restore .
2. Update the virus definitions. Reboot computer in SafeMode;
3. Delete the IE temp files,some W32.IRCBot.DCN temp file exisit there.
4.If you failed to remove W32.IRCBot.DCN,please go to our remove help forum:http://help.antiviruses123.com
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