The Plus HD malware is an extension installed in your browser that displays advertisements such as injected banners and text-links. If when using your browser you see text as “Ads by Plus HD”, then most likely you have been infected with a type of malware/adware that is designed to hijack your settings and display unrelated ads. This is also a tell-tail sign that your PC has been infected with ad-injection adware as well as other piggybacked malware. While this particular infection is more consistent with adware and PUPs (potentially unwanted programs), we classify it as malware as it does perform very malicious behaviors that can compromise your PCs security and your overall privacy. This includes displaying ads for other malware via malvertising, and in many cases it displays compromised ads that serve up exploits that will infect your computer with various trojans or bots as the ad-networks it utilizes are subpar and known to be taken over by malicious malware distributors.
Once infected, this malware will display various types of advertisements that range from banners to pop-ups, pop-overs as well as text-links (underlined words that display hover popups). Advertisements from Plus HD will vary as “Ads by Plus HD”, “Ad by Plus HD” or “Brought by Plus HD” and are often shown as boxes containing large blocks, video or sound advertising, coupons and additional pop-ups. These advertisements are often based on keywords found in the content of the underlying website your are visiting. Once added by the running extension (Chrome), addon (Firefox) or Browser Helper Object/BH (Internet Explorer), new ads will be injected within the content of the page or will directly overwrite existing legitimate ads. Clicking on any of these ads may trigger a pop-up window, redirecting your browser to unwanted advertisements or dubious online scams which try to force you to install a fake Flash Player, Browser or Media Player upgrades. These fake upgrades contain more malware, and installing them typically causes a high-risk of privacy or identity theft.
While the malware itself is promoted as a utility that “enhances” search results or quick access to relevant image, video and so on. Plus HD gets installed on the computer through third-party apps coming from various sources such as pay-per-install programs or download portals. Programs where this adware is packed is similarly hosted on various reputable websites, thus you must take extra caution when installing freeware or shareware. Once inside computer, Plus HD adware alters settings on the browser which will lower your overall security. It drops add-ons and extensions that may result in the manipulation of search results, home page and new-tab hijacking as well as lowers your PC’s security settings and increases your risk to additional malicious programs being installed.