'Adobe Flash Player is out-of-date' Pop-Up

'Adobe Flash Player is out-of-date' is an annoying pop-up that tries to mislead the user into downloading harmful content. There can be two reasons for seeing this message. If it appears on only a few sites, it is likely that they have been compromised. In this case, the PC is not affected and the user should just ignore the message in order to maintain the security. However, sometimes people report that this message pops up on many different domains. This can indicate the presence of a browser hijacker that has most likely entered as a bundle to some freeware. It this is the case, the user may also notice other modifications such as a new search engine, an altered homepage or some ads. If the person believes in the scam and agrees to install the "new version", he will likely have his system infected by different types of malware. As a precautionary measure, all updates should be done through the official page of the relevant product. The hijacker should be deleted quickly in order to keep the system safe.