Trojan.Mebromi

Posted: September 19, 2011

Threat Metric

The Threat Meter is a malware assessment that SpywareRemove.com's research team is able to give every identifiable malware threat. Our Threat Meter includes several criteria based off of specific malware threats to value their severity, reach and volume. The Threat Meter is able to give you a numerical breakdown of each threat's initial Threat Level, Detection Count, Volume Count, Trend Path and Percentage Impact. The overall ranking of each threat in the Threat Meter is a basic breakdown of how all threats are ranked within our own extensive malware database. The scoring for each specific malware threat can be easily compared to other emerging threats to draw a contrast in its particular severity. The Threat Meter is a useful tool in the endeavor of seeking a solution to remove a threat or pursue additional analytical research for all types of computer users.

The following fields listed on the Threat Meter containing a specific value, are explained in detail below:

Threat Level: The threat level scale goes from 1 to 10 where 10 is the highest level of severity and 1 is the lowest level of severity. Each specific level is relative to the threat's consistent assessed behaviors collected from SpyHunter's risk assessment model.

Detection Count: The collective number of confirmed and suspected cases of a particular malware threat. The detection count is calculated from infected PCs retrieved from diagnostic and scan log reports generated by SpyHunter.

Volume Count: Similar to the detection count, the Volume Count is specifically based on the number of confirmed and suspected threats infecting systems on a daily basis. High volume counts usually represent a popular threat but may or may not have infected a large number of systems. High detection count threats could lay dormant and have a low volume count. Criteria for Volume Count is relative to a daily detection count.

Trend Path: The Trend Path, utilizing an up arrow, down arrow or equal symbol, represents the level of recent movement of a particular threat. Up arrows represent an increase, down arrows represent a decline and the equal symbol represent no change to a threat's recent movement.

% Impact (Last 7 Days): This demonstrates a 7-day period change in the frequency of a malware threat infecting PCs. The percentage impact correlates directly to the current Trend Path to determine a rise or decline in the percentage.

Threat Level:	8/10
Infected PCs:	16

First Seen:	September 17, 2011
OS(es) Affected:	Windows

Mebromi or Trojan.Mebromi is a rootkit that compromises basic components of your PC, including both the BIOS and Master Boot Record. Other attacks by Mebromi may vary with its configuration and the instructions that Mebromi receives – although malware analysts have confirmed that Mebromi also contacts a remote attack server and can download other malicious files. Although Mebromi was identified in 2011, Mebromi variants have been identified in 2012, and any Mebromi infection still should be considered a threat to your computer. Because removing Mebromi manually can cause permanent damage to essential system components, using anti-rootkit and anti-malware programs to find and delete Mebromi is always encouraged whenever possible.

Mebromi: Relishing the Art of the Bootkit

Mebromi is of some minor historical significance due to being one of the first confirmed rootkits with 'bootkit' properties – AKA, the capability to corrupt the Master Boot Record or MBR. While becoming more commonplace in 2012-era rootkits, in 2011, Mebromi's bootkit attack was relatively novel and shined new light on the importance of security for the MBR and BIOS. In spite of the landmark sophistication of its attacks, Mebromi has had limited distribution, and most attacks by Mebromi were considered targeted, with a majority of victims being located in China and nearby regions. SpywareRemove.com malware research team rates the possibility of acquiring a Mebromi infection fairly unlikely, assuming that you use standard online safety measures and dutiful anti-malware software.

Mebromi conceals itself in a hidden Recycle Bin directory and attacks the Registry before Mebromi accesses your BIOS. If your PC uses AwardBIOS, Mebromi will infect the BIOS and, in turn, cause it to infect the Master Boot Record. This allows Mebromi and related PC threats to launch themselves automatically – even before your operating system starts to load. SpywareRemove.com malware researchers note that removing Mebromi will require either a PC security expert or powerful anti-malware software to guarantee that your PC isn't damaged during the disinfection process. Damage to either the MBR or BIOS can cause your PC to become unusable, although it may be repaired from system backups.

Digging Mebromi Out of Your System Files

Anti-malware programs may detect Mebromi by various aliases, including Win-Trojan/Mybios.5632, Troj/MyBios-C, Trojan.Bootkit.1, Rootkit.Win32.Mybios.a and Trojan:WinNT/Wador.A. All known variants of Mebromi are limited to Windows compatibility but may infect many different versions of Windows, including Windows 95 up to Windows 7.

Other than a few extra system files and subtle changes to system components, Mebromi doesn't display symptoms that could make its attacks easily-detectable. Ordinarily, anti-malware products should be used to detect Mebromi, although SpywareRemove.com malware experts warn that unsophisticated anti-malware scanners often fail to detect PC threats like Mebromi that make use of rootkit techniques to conceal themselves.

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:

C:\calc.exe

File name: C:\calc.exe
File type: Executable File
Mime Type: unknown/exe
Group: Malware file

C:\bios.bin

File name: C:\bios.bin
File type: Binary File
Mime Type: unknown/bin
Group: Malware file

C:\my.sys

File name: C:\my.sys
File type: System file
Mime Type: unknown/sys
Group: Malware file

%Temp%\cbrom

File name: %Temp%\cbrom
Group: Malware file

Trojan.Mebromi.A