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The 17 most dangerous places on the internet

They're not the usual suspects... you may be surprised

The scariest sites on the net? They're not the ones you might suspect. Here's what to watch for and how to stay safe, in our list of the 17 scariest places on the internet.

Threat 9: Malicious PDFs that try to fool you into installing malware

The place: Hacked websites, plus your inbox

As Microsoft has become more serious about Windows security over the past few years, would-be attackers have had to find new ways to infect PCs. Attacking flaws in Adobe Acrobat is one of these newer methods. So-called poisoned PDFs are PDF files that have been crafted in such a manner that they trigger bugs in Adobe Reader and Adobe Acrobat; posted on a hijacked website, they may let an attacker commandeer your PC and access your files and personal info.

A newer variant takes an otherwise innocent-looking PDF document and inserts malware into it. Adobe Reader may pop up an alert asking if you want to run the malware, but hackers can edit those messages to trick you into opening the file. How serious is this problem? In 2009, attacks using malicious PDFs made up 49 percent of Web-based attacks, according to security firm Symantec.

If you have to go there: First, always make sure that you're running the latest version of Adobe Reader. You can also use a different PDF reader, such as Foxit Reader. This can protect you from attacks on holes in Adobe Reader itself, but it won't make you immune to all PDF attacks, such as the newer ones that embed malware inside the PDFs. Make sure, also, that you update to Adobe Reader 9.3.3 or later (Reader 8 users should update to version 8.3.3 or later); these updates change the way Adobe Reader handles non-PDF attachments and reduce the risk from such attacks.

You can turn off Adobe Reader's ability to open non-PDF attachments by going to Preferences, clicking Trust Manager, and unchecking Allow opening of non-PDF file attachments with external applications.

The next major release of Acrobat and Reader will provide a new 'protected mode' against these attacks.

Threat 10: Malicious video files using flaws in player software to hijack PCs

The place: Video download sites

Attackers have been known to exploit flaws in video players such as QuickTime Player and use them to attack PCs. The threats are often 'malformed' video files that, like malicious PDFs, trigger bugs in the player software that let the attackers in to spy on you, plant other malware, and more.

If you have to go there: Keep your player software up-to-date. Apple and Microsoft periodically release patches for QuickTime and Windows Media Player, respectively. Avoid downloading videos at random. Stick to well-known video sites such as YouTube, or to download services like iTunes.

Threat 11: Drive-by downloads that install malware when you visit a site

The place: Hacked legitimate sites

A drive-by download occurs when a file downloads and/or installs to your PC without you realizing it. Such downloads can happen just about anywhere. Some sites are built to lure people into a drive-by download; but in a common attack method, criminals will hack a web page, often on an otherwise legitimate site, and insert code that will download malware to your computer.

If you have to go there: The first thing to do is to keep your security software up-to-date, and to run regular malware scans. Many security suites can flag suspicious downloads.

NEXT PAGE: Fake antivirus software

  1. They're not the usual suspects
  2. Torrent sites
  3. Your smartphone
  4. Malicious PDFs
  5. Fake antivirus software
  6. 'Free electronics' sites
  7. What happens when you surf unprotected
  8. Tips from the pros


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