1. Symantec/
  2. Security Response/
  3. Trojan.FireAnvil


Risk Level 1: Very Low

September 11, 2002
February 13, 2007 11:54:52 AM
Also Known As:
Trojan.Win32.FireAnvil [AVP], Troj/FireAnv-A [Sophos], FireAnvil application [McAfee]
Trojan Horse
Systems Affected:

One particular release of the commercial product Firehand Ember v5.2.3 by Firehand Technologies Corporation contains built-in functionality that may cause data corruption.

If you register your copy of the Firehand Ember product by entering the string "czy czy" in the "Registered User ID" field, as shown here:

the program's payload will do the following:

It enumerates all of the files on a Windows installation partition (by default, it is C:\) and rewrite the first bytes of every file with the following string:

CzY CrAcKiNg CrUe! We CrACk EvErYtHiNg!

This will lead to total data corruption. When the payload performs its actions, you see the following string in a dialog box:

CrAcKiNg SoFtWaRe! PlEaSe WaIt!

An example of this is shown here. Many items are not displayed correctly due to the data corruption that was caused by the Trojan.

The Firehand Ember v5.2.3 program contains a hard-coded list of banned users to which this software cannot be registered. This was implemented to avoid registration of serial numbers that were leaked to the Internet. The "czy czy" account is also in the list of the banned accounts. However, for this particular account the software triggered its built-in destructive payload, which was implemented by someone who did have or currently has access to the source code of this software. This might be a former or present employee of Firehand Technologies Corporation.

The current version of the software contains no destructive payload since the "czy czy" account has been transferred into the list of the banned accounts with no destructive payload.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • 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.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a 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.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. 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.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Serghei Sevcenco
Summary| Technical Details| Removal

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