Backdoor.HackTack

SUMMARY

Backdoor.HackTack is a backdoor Trojan horse. It has extensive control capabilities, and it allows a hacker to access the computer.

Protection

• Virus Definitions (Intelligent Updater) August 9, 2000

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

Backdoor.HackTack is usually installed in the C:Windows folder. The file name that it uses varies; a common name is Expl32.exe. The name is chosen to make it appear to be a normal system file.

It also changes a registry key so that the Trojan is run each time that you start Windows. Typically it adds a value such as

Explorer32  C:WINDOWSExpl32.exe

to the registry key

HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun


This backdoor allows a hacker to have a great degree of control over the compromised system, including:

• Executing files
• Disabling the keyboard
• Disabling the mouse
• Opening Internet connections
• Displaying messages or graphics

Recommendations

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.

REMOVAL

To remove this Trojan, delete all files that are detected as Backdoor.HackTack, and remove the value that it added to the registry.

To remove the Trojan:

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
3. Run a full system scan.
4. Write down the names of all files that are detected as Backdoor.HackTack, and then delete the files.

To edit the registry:

CAUTION: We strongly recommend that you back up the system registry before you make any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure that you modify only the keys that are specified. Please see the document How to back up the Windows registry before you proceed.

1. Click Start, and click Run. The Run dialog box appears.
2. Type regedit and then click OK. The Registry Editor opens.
3. Navigate to the following key:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun
   
4. In the right pane, look for a value that refers to any of the files that were detected as Backdoor.HackTack.
5. Delete any such values that you find.
6. Click Registry, and click Exit to save the changes.