Trojan:JS/Medfos.B

Posted: October 8, 2012

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.

Ranking:	8,725
Threat Level:	9/10
Infected PCs:	2,642

First Seen:	October 8, 2012
Last Seen:	October 15, 2023
OS(es) Affected:	Windows

Trojan:JS/Medfos.B is a malicious Chrome extension that redirects your searches and exposes you to irrelevant advertisement-based sites. Trojan:JS/Medfos.B is often, but not always, installed by Trojan:Win32/Medfos.B, which malware experts have linked to the presence of Translate This! Toolbars. Although Trojan:JS/Medfos.B's main attacks are designed for Chrome, Trojan:Win32/Medfos.B can be used for a variety of attacks that can affect other types of browsers. Due to the presence of related PC threats and the fact that Trojan:JS/Medfos.B uses file names that make Trojan:JS/Medfos.B appear to be a safe browser component, it's suggested that you utilize anti-malware scanners to find and remove Trojan:JS/Medfos.B, and, hopefully, all other Trojans that are linked to its presence.

When Your Online Searches Get Out of Sorts with Trojan:JS/Medfos.B

Trojan:JS/Medfos.B often is installed by a related Trojan from the Medfos family, Trojan:Win32/Medfos.B to achieve a series of browser-redirecting attacks against the compromised computer. From Chrome's extension manager, Trojan:JS/Medfos.B will appear to be an update-management add-on – even though Trojan:JS/Medfos.B doesn't have any functions that relate to that purpose. A separate add-on, Translate This!, is also installed in a separate browser (Mozilla Firefox). Visible malware researchers have noted below.

Trojan:JS/Medfos.B redirects both attempts to access and attempts to search with the following sites, which are forced to redirect you to unrelated websites. Secondary sites tend to be focused on pay-per-click revenue and advertisements, although they may also display hostile content. Sites affected include:

Yahoo
Bing
Google
Ask
AOL

Examples of sites that Trojan:JS/Medfos.B may redirect your browser towards include thechromeweb.com and chrome-bulletin.com. These sites may be a source of drive-by-downloads, phishing efforts and other attacks, although their main danger simply is the waste of time that's caused by their advertisements.

Why Other Browsers Aren't Safe from Trojan:JS/Medfos.B

Even though Trojan:JS/Medfos.B is designed as an add-on for Chrome, SpywareRemove.com malware analysts have found some cases of Trojan:JS/Medfos.B being installed on PCs that don't use this browser. More importantly, Trojans associated with Trojan:JS/Medfos.B have been known to redirect Internet Explorer and Firefox (the latter with the help of another malicious add-on: Trojan:JS/Medfos.A). Generally, Trojan:JS/Medfos.B is always part of a multicomponent attack, and you should always scan your entire PC to find and remove Trojan:JS/Medfos.B and the source of its presence on your computer.

Trojan:JS/Medfos.B and its relatives were identified in mid-2012, and anti-malware products with outdated databases may not be able to identify or remove Trojan:JS/Medfos.B effectively. Changes to your browser should also be avoided until Trojan:JS/Medfos.B is deleted, since these changes can be reverted and will not do anything to bring a permanent stop to redirect attacks by Trojan:JS/Medfos.B and its cohorts.

Trojan:JS/Medfos.B

Threat Metric

When Your Online Searches Get Out of Sorts with Trojan:JS/Medfos.B

Why Other Browsers Aren't Safe from Trojan:JS/Medfos.B

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