Threat Explorer

The Threat Explorer is a comprehensive resource consumers can turn to for daily, accurate, up-to-date information on the latest threats, risks and vulnerabilities.

Infostealer.Astaroth

Infostealer.Astaroth

Discovered:
July 10, 2019
Updated:
July 10, 2019
Infection Length:
100,000 bytes
Systems Affected:
Windows
Infostealer.Astaroth is a Trojan horse that steals information from the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version July 10, 2019 revision 004
  • Latest Rapid Release version July 10, 2019 revision 004
  • Initial Daily Certified version July 10, 2019 revision 007
  • Latest Daily Certified version July 10, 2019 revision 007
  • Initial Weekly Certified release date July 10, 2019
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
The Trojan arrives on the compromised computer via malicious links contained in spam email.

Once the user clicks on the malicious link a ZIP file is downloaded.

The ZIP file contains an LNK file that runs the Windows Management Instrumentation Command line (WMIC) tool to download an XSL file from remote location.

The XSL file contains JScript code that runs another WMIC command to download another XSL from a remote location and then execute the JScript code inside that file.

The second piece of JScript code downloads multiple files using bitsadmin.exe and then decodes them using certutil.exe.

One of the of the decoded binaries (DLL) is loaded by regsvr32.exe.

The loaded DLLs decode and load other DLLs.

The Trojan may then steal information from web browsers and log keystrokes.

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.
You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan. If that does not resolve the problem you can try one of the options available below.



FOR NORTON USERS
If you are a Norton product user, we recommend you try the following resources to remove this risk.


Removal Tool
Use our tools to remove aggressive risks from your computer.

Infected Windows system files may need to be repaired using the Windows installation CD .


How to reduce the risk of infection
Check out our extensive collections of helpful advice and tips on how to stay safe online .


FOR BUSINESS USERS
If you are a Symantec business product user, we recommend you try the following resources to remove this risk.


Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.


Removal Tool

If you have an infected Windows system file, you may need to replace it using the Windows installation CD .



MANUAL REMOVAL
The following instructions pertain to all current Symantec antivirus products.


1. Performing a full system scan
For information on how to run a full system scan using your Symantec product, follow the guidance given in the product's Help section.


2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.
Writeup By: Mingwei Zhang