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W32.Francette.Worm - Security Advisory
My system is secure as hell, but this worm is attacking every few hours. Virus scanner is picking it up and firewall aint blocking it. nightmare.
W32.Francette.Worm is a worm that exploits the DCOM RPC vulnerability (described in Microsoft Security Bulletin MS03-026) using TCP port 135, as well as the Microsoft IIS Web Server Folder Traversal vulnerability (described in Microsoft Security Bulletin MS00-078). The existence of the file syshost.exe is an indication of a possible infection.
This worm is written in Borland Delphi and is packed with ASPack.
When W32.Francette.Worm is executed, it performs the following actions:
Adds the values:
"Microsoft IIS"="syshost.exe"
to the registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
Calculates a random IP address.
Attempts to connect to the randomly generated IP addresses.
Once the worm identifies a computer as being active on the network, it sends data to TCP port 135, which exploits the DCOM RPC vulnerability.
Then, it creates a remote shell on the vulnerable host and instructs the victim computer to use FTP to connect to a ftp server whose address is hard-coded into the worm.
Downloads an updated version of itself as syshost.exe and executes it on the remote machine.
Uses the Microsoft IIS Web Server Folder Traversal vulnerability to exploit unpatched servers running IIS, in order to download the following files to the C:\Winnt\System32 folder:
nt_ddr.exe (detected as DebPloit.Exploit)
Syshost.exe
and then execute them.
Connects to a specific IRC channel on a specific IRC server on TCP port 6669 or 6667 to receive remote instructions to:
Perform Denial of Service (DoS) Attacks
Execute commands
Download files
Scan for open ports on remote machines
Flood IRC channels
Symantec 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.
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.
The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.
Disable System Restore (Windows Me/XP).
Update the virus definitions.
Do one of the following:
Windows 95/98/Me: Restart the computer in Safe mode.
Windows NT/2000/XP: End the Trojan process.
Run a full system scan and delete all the files detected as W32.Francette.Worm.
Reverse the changes that the Trojan made to the registry.
For specific details on each of these steps, read the following instructions.
1. Disabling System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.
Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.
Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.
For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
"How to disable or enable Windows Me System Restore"
"How to turn off or turn on Windows XP System Restore"
For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.
2. Updating the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to the Virus Definitions (LiveUpdate).
Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted on U.S. business days (Monday through Friday). You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to the Virus Definitions (Intelligent Updater).
The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.
3. Restarting the computer in Safe mode or ending the Trojan process
Windows 95/98/Me
Restart the computer in Safe mode. All the Windows 32-bit operating systems, except for Windows NT, can be restarted in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode."
Windows NT/2000/XP
To end the Trojan process:
Press Ctrl+Alt+Delete once.
Click Task Manager.
Click the Processes tab.
Double-click the Image Name column header to alphabetically sort the processes.
Scroll through the list and look for Cnqmax.exe.
If you find the file, click it, and then click End Process.
Exit the Task Manager.
4. Scanning for and deleting the infected files
Start your Symantec antivirus program and make sure that it is configured to scan all the files.
For Norton AntiVirus consumer products: Read the document, "How to configure Norton AntiVirus to scan all files."
For Symantec AntiVirus Enterprise products: Read the document, "How to verify that a Symantec Corporate antivirus product is set to scan all files."
Run a full system scan.
If any files are detected as infected with W32.Francette.Worm, click Delete.
5. Reversing the changes made to the registry
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WARNING: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified keys only. Read the document, "How to make a backup of the Windows registry," for instructions.
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Click Start, and then click Run. (The Run dialog box appears.)
Type regedit
Then click OK. (The Registry Editor opens.)
Navigate to the key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
In the right pane, delete the value:
"Microsoft IIS"="syshost.exe"
Exit the Registry Editor.
___________________
" You bet your ass we're all alike... we've been spoon-fed baby food at school when we hungered for steak... the bits of meat that you did let slip
through were pre-chewed and tasteless. We've been dominated by sadists, or ignored by the apathetic. The few that had something to teach found us will-
ing pupils, but those few are like drops of water in the desert."
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