The Astaroth Trojan is a dangerous weapon used against computer users worldwide. It infects mainly via infected software installers. Our article gives an overview of its behavior according to the collected samples and available reports, also it may be helpful in attempting to remove the virus.
|Short Description||The Astaroth Trojan is a computer virus that is designed to silently infiltrate computer systems.|
|Symptoms||The victims may not experience any apparent symptoms of infection.|
|Distribution Method||Software Vulnerabilities, Freeware Installations, Bundled Packages, Scripts and others.|
|Detection Tool|| See If Your System Has Been Affected by Astaroth Trojan |
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|User Experience||Join Our Forum to Discuss Astaroth Trojan.|
Astaroth Trojan – Distribution Methods
The Astaroth Trojan is being spread in an ongoing campaign, the reports indicate that the majority of affected victims are from Brazil and Europe. This is a very dangerous threat as it uses the method of exploiting vulnerabilities in the machines, specifically a weakness in a popular anti-virus product (Avast!). The mechanism is unusual — the hackers abuse the legitimate Windows Service called BITSAdmin which is used to download, upload and manage jobs, part of the “Background Intelligent Transfer Service” feature available for Windows developers. Instead of programming it for the usual tasks it is programmed to download malware threats, in this case the Astaroth Trojan.
Email Phishing messages that are sent in a SPAM-like manner are sent to the targets by impersonating Microsoft or other trusted vendors. They have archive attachments in the .7zip format. When opened inside there will be a .lnk file which when executed will spawn the relevant wmic.exe process. This will lead to an attack that is known as a “XSL Script Processing Attack”.
In practice the hackers abuse a trusted binary which will run the script, thus hijacking the Avast anti-virus process. According to the security reports this is not an injection or a privilege escalation. Instead the avast binaries are programmed to run the malware files. The avast engine itself contains a self-protection mechanism which does not permit any abuse of the application itself. The vendor is currently patching the software.
The identity of the criminals is not known at the moment, an investigation is ongoing into the possible origins of the threat. We anticipate that this payload-based infection mechanism can be used with other similar methods:
- Infected Documents — The criminals the virus installation script in documents across all popular variants: text documents, spreadsheets, databases and presentations. When they are opened a macros execution prompt will appear asking the victim users to enable the scripts, the quoted reason is that this is required in order to correctly view the files.
- Infected Application Installers — The criminals can take the installers of popular applications and modify them to include the Astaroth Trojan. This is done by acquiring the legitimate setup files from their official sources and inserting the appropriate virus installation code. Usually applications that are frequently downloaded by end users: system utilities, creativity suites, productivity apps and etc.
- File-Sharing Networks — The files can be spread via peer-to-peer networks like BitTorrent which are popular for distributing both legitimate and pirate content.
Astaroth Trojan – Detailed Description
As soon as the Astaroth Trojan infection is triggered a series of dangerous actions will occur. The relevant BITSAdmin utility will be programmed to download a malicious payload from a predefined hacker-controlled server. The code analysis reveals that the the malware is obfuscated as image files or data without a specific extension. This is done in order to evade regular anti-virus scans.
We anticipate that future versions may include a standalone security bypass which can locate security software that can potentially block the virus execution: anti-virus products, firewalls, intrusion detection systems and virtual machine hosts.
A dangerous component that is part of the Trojan’s code base is the information gathering module:
- Personal Information — The Trojan engine is capable of acquiring data that can be used to directly expose the identity of the victims by looking for strings such as a person’s real name, nicknames, interests, phone number, address and any stored account credentials. The collected information can be used for various crimes including financial abuse, identity theft and blackmail.
- Machine Information — The Trojan engine can create an identifier that is assigned to each compromised machine. It is done using an algoirthm that takes its input parameters from values such as the installed hardware parts list, user settings and certain operating system environment values.
The gathered information will then be sent to the criminal controllers via a network connection to their C&C servers. This allows them to take over control of the victim machines, files theft and to spy on the users. What’s more dangerous is that the Trojan can be programmed to interact with the Windows Volume Manager, thus giving it the ability to access removable storage devices and network shares.
Other malicious actions that can follow include the following:
- Persistent Installation — The Astaroth Trojan code will be launched every time the computer is powered on. This step in most of the cases will also disable access to the boot menu options thereby making most of the manual user removal guides useless.
- Windows Registry Changes — Modification to the Windows Registry values is a common action undertaken by many malware of this category. Changes to strings that are used by the operating system can cause overall performance degradation and stability issues. If any third-party applications or services values are changed then the accompanying programs may quit unexpectedly with errors.
- Additional Payload Delivery — The Trojan client can be programmed to download other threats to the infected computers.
- Data Removal — Important files can be deleted automatically as soon as the Astaroth Trojan infection is triggered. Common data that is to be removed includes System Restore Points, Shadow Volume Copies and Backups. Effective restore of the compromised computers is done by using a combination of an effective anti-spyware utility and a data recovery program.
Depending on the forthcoming versions and future attack campaign we might see a radically different Astaroth Trojan release in the near future.
Remove NtCrypt Crypter Completely
To remove Astaroth Trojan manually from your computer, follow the step-by-step removal tutorial written down below. In case this manual removal does not get rid of the miner malware completely, you should search for and remove any leftover items with an advanced anti-malware tool. Such software can keep your computer secure in the future.