Backdoor.Acropolis

Printer Friendly Page

Discovered: February 16, 2001
Updated: February 13, 2007 11:35:17 AM
Type: Trojan Horse


This Trojan horse permits a remote operator to control an infected system. The name of the Trojan horse is Acropolis 1.0, and it is detected as Backdoor.Acropolis.

Antivirus Protection Dates

  • Initial Rapid Release version February 16, 2001
  • Latest Rapid Release version July 13, 2018 revision 019
  • Initial Daily Certified version February 16, 2001
  • Latest Daily Certified version July 14, 2018 revision 004

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Dmitry Reyder

Discovered: February 16, 2001
Updated: February 13, 2007 11:35:17 AM
Type: Trojan Horse


When launched, the Trojan horse opens a network connection on ports 32791 and 45673. This gives a remote operator the capability to use your computer to send messages using mIRC. These messages may contain attached files. It is possible, but not confirmed, that the Trojan horse could also be used to control email programs.

In addition, the Trojan horse modifies the Windows registry as follows:

  • It adds the value:

    Winport.com <Trojan file name and path>

    to the subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\RunServices

    This causes the Trojan horse to run at system startup.
  • It creates the key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\UDP Ports

    The Trojan horse uses this key to store information in the following variables:

    Password
    From
    To
    Host
    Port
    Server
    Target
    Name

    This information is used for the remote control of the infected system.

Finally, the Trojan horse scans all running programs and services, and then it launches Spool32.exe (the Windows print spooling application). The reason for this is not currently known.

Recommendations

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: Dmitry Reyder

Discovered: February 16, 2001
Updated: February 13, 2007 11:35:17 AM
Type: Trojan Horse


To remove this Trojan horse, you need to delete the registry entries it created, restart the computer, and then run a full system scan. Follow these steps to do this:

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

  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 subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\RunServices
  4. In the right pane, delete the following value:

    Winport.com <Trojan file name and path>
  5. Navigate to and delete the following subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\UDP Ports
  6. Close the Registry Editor.
  7. Restart the computer.
  8. Run LiveUpdate to make sure that you have the most recent virus definitions.
  9. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
  10. Delete any files that are detected as Backdoor.Acropolis.


Writeup By: Dmitry Reyder