Trojan.MircAbuser.dr pretends to install a useful tool. However, this file installs Mirc32 on the computer and creates hidden files that allow a hacker to access the affected computer and use it for a Denial of Service attack. These hidden files are detected as Trojan.MircAbuser.
Trojan.MircAbuser is installed on the computer by an executable file, named "CD-R Doubler.exe", that is detected as Trojan.MircAbuser.dr.
When executed, this file appears to install a useful tool such as a CD speed doubler; however, this program:
Installs Mirc32 in the C:\Mirc folder.
Creates a copy of Mirc32.exe in the C:\Program Files folder. The file name of this copy is Schd.exe, but it is just a renamed Mirc32.exe file.
Creates a shortcut to the copy in C:\Windows\Start Menu\Programs\StartUp so that the computer is connected to mIRC as much as possible.
Trojan.MircAbuser generally consists of three hidden .ini script files that are used by the Mirc32 copy that is installed along with this Trojan horse. These hidden files are installed in the C:\Program Files folder and allow a hacker to access the affected system and use it for a Denial of Service attack.
One indication that the installer file has been launched is that a small envelope icon appears in the system tray.
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 (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.
To recover from this infection:
Run LiveUpdate to make sure that you have the most recent virus definitions.
Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
If any files are detected as Trojan.MircAbuser or Trojan.MircAbuser.dr, click Delete.
Use Windows Explorer to delete the copy of Mirc32.exe in the C:\Program Files folder, and the shortcut in the C:\Windows\Start Menu\Programs\StartUp folder.
