Security Checkup - Safari and Preview, Part 1
Macintosh computers are shipped with a setting in Safari that should probably be changed. They are set so that “safe” files will open automatically. However, some of these “safe” files are not so safe.
“Safe” files include movies, pictures, sounds, PDF and text documents, and disk images and other archives.
While I will agree that on the Mac movies, pictures, sounds, and text documents are almost always “safe,” the other three are not nearly as “safe.” Let’s consider the others.
When your Mac was shipped, the default viewer for PDF documents was set to be Apple’s own Preview application. It is safe, but the other popular software to view PDF files, Adobe Reader, is not. There are lots of web sites that have links to and recommend Adobe Reader. Most of those sites are written by Windows users and for PC’s, there are few free Windows applications that can handle PDF chores.
On your Macintosh, Preview is a faster, better and safer application choice. If your computer is set to use Preview to view PDFs, the icon will look like this:
These are the “good” icons.
If your computer is set up to use Adobe Reader, it will look like this:
This is the “bad” icon. If your computer is set to use Adobe Reader, pdf icons will look like this. Unfortunately, there are a number of vulnerability issues associated with it. Even with frequent updates, Adobe Reader is still a problem.
Here is the way have Apple’s Preview open PDF files.
First, find a PDF file on your computer. To find such a file, open a new Finder window:
In that window, type .pdf in the search area and click the buttons for “This Mac” and “File Name.”
Click on a PDF file to select it.
The press Command - I on the keyboard or go to File > Get Info in the Finder.
You will then see a window similar to this. Notice the tiny “disclosure triangles” beside each item. If the “Open with” area is not displayed, click that tiny triangle to view the information.
Choose Preview. It could be at the top of the list, or it could be further down in the body of the list.
Now, press the “Change All…” button to make this choice the default.
From now on (or until sneaky Adobe Reader convinces you select it again) PDF files will open in Safari.
As for Disk Images, Wikipedia defines them this way:
A disk image is a single file or storage device containing the complete contents and structure representing a data storage medium or device, such as a hard drive, tape drives, floppy disk, CD/DVD/BD and key drive, although an image of an optical disc may be referred to as an optical disc image. A disk image is usually created by creating a complete sector-by-sector copy of the source medium and thereby perfectly replicating the structure and contents of a storage device.
So, put simply, a disk image looks like this.
When it is opened, it will look similar this on your desktop:
It will look like this in the Finder Sidebar:
Archived or Zipped files look similar to these:
Both Disk Image Files and archived files could be malicious. The vast majority are quite safe, but if you do not recognize the file or your cannot remember where it came from, it is safest to put the file in your trash can and empty it!
We are certainly not finished here, but this post is long enough. Stay Tuned for Security Checkup - Safari and Preview, Part 2. I am working on it NOW!