Adware refers to programs that display advertising using any means: pop-ups, banners, changes to the browser home page or search page, etc. The advertisements could be associated with the products or services offered by the creator of the program or by third-parties.
Adware can be installed in a number of ways, on some occasions without users' consent, and either with or without users' knowledge of its function.
It affects productivity, preventing tasks from being carried out:
- In the affected computer:
it displays pop-up windows; causes system slowdowns.
It reduces the security level of the computer:
it terminates processes belonging to security tools, such as antivirus programs and firewalls, leaving the computer defenseless against attacks from other malware; it changes system permissions, decreasing the security level.
It uses stealth techniques to avoid being detected by the user:
- It uses techniques included in its code to hide itself while it is active.
- It deletes the original file from which it was run once it is installed on the computer.
It uses several methods in order to avoid detection by antivirus companies:
- It terminates its own execution if it detects that it is being executed in a virtual machine environment, such as VMWare or VirtualPC.
XPAntiMalware.A uses the following propagation or distribution methods:
- Exploiting vulnerabilities with the intervention of the user: exploiting vulnerabilities in file formats or applications. To exploit them successfully it needs the intervention of the user: opening files, viewing malicious web pages, reading emails, etc.
- Via Internet, exploiting remote vulnerabilities: attacking random IP addresses, in which it tries to insert a copy of itself by exploiting one or more vulnerabilities.
- Email: sending emails that include a copy of itself as an attachment. The computer is infected when the attachment is run.
- Peer-to-peer (P2P) file sharing programs: it makes copies of itself with enticing names in shared folders belonging to these programs. Other users of this type of networks then voluntarily download and run the infected files.