Adware is any program with the primary function of displaying advertisements. As a result, any particular adware program can only be as dangerous as the danger or safety of the (typically third-party) advertisements that it’s designed to display. Adware can vary significantly in terms of their threat-level, with some types of adware being relatively harmless while others are used to facilitate serious attacks against your PC.
Although identifying the presence of installed adware is rarely a problem, our malware research team has made note that their initial installation routines are often difficult to spot. Adware is one of the most common types of PC threats to be distributed along with other types of software, particularly browser add-ons, toolbars, instant messenger accessories and peer-to-peer downloading clients. Benign adware usually will allow you to opt-out of installing it, although this is rarely the default selection during installation. Malicious adware may not even announce its installation at all and can also be used to expose you to other PC threats, including common phishing scams and promotional messages for rogue security programs.
Common Symptoms of Adware Attacks
Rivaled only by scamware for the sheer visibility of their symptoms, adware programs are usually discovered quickly after installation, since their purpose is to display very obvious advertisements – sometimes in massive quantities. Advertisements from adware can take the form of unwanted browser pop-ups, web page alterations that insert additional ad-related content or keyword-based links that are added to website text. Familiarity with the websites that you’re browsing so that you can spot ‘out of place’ advertisements can help victims identify adware attacks – although in many cases, all one needs to do is watch for a massive stream of pop-ups. A few types of adware will also use audio-only advertisements that can launch without any obvious triggers on your part.
Some but not all types of adware can also include extra functions that may prove harmful to your PC. In particular, our malware researchers have found that malicious forms of adware often update themselves without your consent and may monitor which websites you visit to deliver ‘relevant’ ads.
The Consequences of an Adware Infection
All of the functions noted earlier can damage the quality of your web-browsing experience by reducing the speed of website loading times and similar performance metrics. Victims of adware infections often report a sharp reduction in the speed and responsiveness of their PCs, which is particularly an issue for systems with limited RAM or other system resources. Advertisements from adware can also block or alter online content in undesirable ways, for example, via pop-ups that refuse to be closed and, therefore, block your ability to see other windows.
Since many forms of adware don’t take precautions to filter out dangerous ad-related content, adware can be responsible for leading victims to online attacks or installation procedures for malicious software. For instance, phishing attacks promoted in adware pop-ups may take on the disguise of a free prize, survey or contest, while fake infection warnings and system scanner pop-ups can be used to install rogue security programs. Adware often resists normal removal methods, although it can be removed easily by competent anti-malware products.