Posted: December 8, 2011
Threat Metric
Threat Level: 9/10
Infected PCs 24

Trojan-Downloader.Win32.VB.aoff Description

Trojan-Downloader.Win32.VB.aoff is a Brazilian banking Trojan which pretends to be a Microsoft anti-malware program. Trojan-Downloader.Win32.VB.aoff targets Windows systems by removing built-in security applications and allows cybercriminals to steal banking credentials from affected computer users. Trojan-Downloader.Win32.VB.aoff affects 'ntldr', the default boot loader on Windows PCs. Trojan-Downloader.Win32.VB.aoff propagates as a link attached to emails. Once PC users click on the malicious link, Trojan-Downloader.Win32.VB.aoff downloads two malicious files from Amazon's Web Services cloud. These files, named 'xp-msantivirus' and 'xp-msclean', worm their way onto the computer's bootloader, a component that gets executed before the startup of the PC's operating system. The aims of the malicious files, promoted as msantivirus and msclean, is to look like legitimate Microsoft anti-virus software and computer cleanup tools, but in reality, they are exactly the opposite.

When these malicious files attack the Microsoft ntldr bootloader, they substitute it with a new, malicious one, a version of GRUB, an open-source bootloader, which they adjust to perform their commands. Without drawing attention to itself, the new bootloader starts the computer into Linux or Unix software that deletes a common Brazilian bank-security plugin, while also eliminating the PC system's built-in Microsoft security program, opening it up to further potential malware attacks. This dubious change takes place before the computer has even booted up; and worse, it automatically deletes itself and resets the original bootloader, so affected users have no idea their security has been compromised. All they're aware of during this whole bait-and-switch is that the bootup is taking a little longer than usual, but the attack clarifies that with a fake message stating to be from Microsoft that says it is actually 'removing malicious files'. You should run up-to-date and reliable anti-virus and anti-malware software on your PC to get rid of Trojan-Downloader.Win32.VB.aoff.

Use SpyHunter to Detect and Remove PC Threats

If you are concerned that malware or PC threats similar to Trojan-Downloader.Win32.VB.aoff may have infected your computer, we recommend you start an in-depth system scan with SpyHunter. SpyHunter is an advanced malware protection and remediation application that offers subscribers a comprehensive method for protecting PCs from malware, in addition to providing one-on-one technical support service.

Download SpyHunter's Malware Scanner

Note: SpyHunter's free version is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter's malware tool to remove the malware threats. Learn more on SpyHunter. If you would like to uninstall SpyHunter for any reason, please follow these uninstall instructions. To learn more about our policies and practices, visit our EULA, Privacy Policy and Threat Assessment Criteria.

Why can't I open any program including SpyHunter? You may have a malware file running in memory that kills any programs that you try to launch on your PC. Tip: Download SpyHunter from a clean computer, copy it to a USB thumb drive, DVD or CD, then install it on the infected PC and run SpyHunter's malware scanner.

Technical Details

File System Modifications

Tutorials: If you wish to learn how to remove malware components manually, you can read the tutorials on how to find malware, kill unwanted processes, remove malicious DLLs and delete other harmful files. Always be sure to back up your PC before making any changes.

The following files were created in the system:

5.exe File name: 5.exe
Size: 237.46 KB (237468 bytes)
MD5: 9c7f6100153538b8f511002b4912352c
Detection count: 36
File type: Executable File
Mime Type: unknown/exe
Group: Malware file
Last Updated: December 9, 2011
file.exe File name: file.exe
Size: 9.72 KB (9728 bytes)
MD5: a3e8e8153ee75d584c112bd0373f8c1e
Detection count: 35
File type: Executable File
Mime Type: unknown/exe
Group: Malware file
Last Updated: December 9, 2011
Home Malware Programs Trojans Trojan-Downloader.Win32.VB.aoff

Leave a Reply

Please note that we are not able to assist with billing and support issues regarding SpyHunter or other products. If you're having issues with SpyHunter, please get in touch with SpyHunter customer support through your SpyHunter. If you have SpyHunter billing questions, we recommend you check the Billing FAQ. For general suggestions or feedback, contact us.