Trojan:JS/Medfos.B Description

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).

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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 and 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, 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 Automatic Detection Tool (Recommended)

Is your PC infected with Trojan:JS/Medfos.B? To safely & quickly detect Trojan:JS/Medfos.B we highly recommend you run the malware scanner listed below.

Posted: October 8, 2012 | By
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Threat Metric
Threat Level: 9/10
Detection Count: 106
Home Malware ProgramsTrojans Trojan:JS/Medfos.B

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