Notebook Security

The Wolfram Language provides users with access to their computer's file system (Files), interprocess communication (WSTP Wolfram Language Functions), evaluation of data as code (Converting between Expressions and Strings), and the ability to run arbitrary external programs (Calling External Programs). While these features enable Wolfram Language users to create powerful programs that can perform truly useful tasks, they bring with them the potential for misuse.

The Wolfram System notebook front end provides three mechanisms for evaluating code: Shift+MacOSXReturnEnter evaluations, initialization cells, and dynamic content.

Shift+MacOSXReturnEnter Evaluations

Because Shift+MacOSXReturnEnter evaluations require user interaction to start them, the Wolfram Language provides no safeguards against potentially malicious code that is evaluated using this mechanism. Users should ensure that they do not perform Shift+MacOSXReturnEnter evaluations on code from untrusted sources. When writing their own code, users should take great care to ensure that the code does not have unintended consequences. For example, the Wolfram Language will not provide a warning when the user evaluates a program to delete files from his or her computer.

Initialization Cells

Initialization cells provide users with a convenient way to evaluate startup code needed by a given notebook when the user first evaluates any input in that notebook. Since this code will be automatically evaluated, likely without the user ever seeing the initialization code, the Wolfram Language will display an alert prompt asking the user to confirm his or her intent to run the initialization code. Users should not evaluate initialization code in a notebook that was obtained from an untrusted source unless the code has been determined to be safe.

Dynamic Content

The Wolfram Language has amazing dynamic interactivity features. Notebooks containing interactive (RefLink[Dynamic, paclet:ref/Dynamic]) content can automatically evaluate code without any additional action by the user, aside from opening the notebook file. Many times this is exactly what the user will want, while other times the user should be alerted before this sort of automatic evaluation takes place.

When the user opens a notebook containing dynamic content, the Wolfram Language will first determine whether the notebook's directory is trusted, untrusted, or neither.

The Wolfram Language provides some options which can be used to configure which notebooks will alert the user about automatic evaluations and which notebooks will not.

TrustedPath

The value of the TrustedPath option is a list of directories that are always trusted by the Wolfram Language. Any notebook file located in any directory in TrustedPath is trusted by the Wolfram Language. The Wolfram Language will never display an alert when a trusted notebook is opened, and the notebook can automatically perform dynamic evaluations.

By default, the TrustedPath option value contains (RefLink[$InstallationDirectory, paclet:ref/$InstallationDirectory]), (RefLink[$BaseDirectory, paclet:ref/$BaseDirectory]), and (RefLink[$UserBaseDirectory, paclet:ref/$UserBaseDirectory]) so that Wolfram System installation files and additional installed applications will be able to display dynamic content without alerting the user.

Here are the directories on your computer that are currently trusted by the Wolfram Language:

Dynamic[Column[ToFileName/@CurrentValue[$FrontEnd,{"NotebookSecurityOptions","TrustedPath"}]]]

"Edit TrustedPath..."

UntrustedPath

The value of the UntrustedPath option is a list of directories that are always untrusted by the Wolfram Language. Any notebook file located in any directory in UntrustedPath is untrusted by the Wolfram Language. The Wolfram Language will always display an alert when an untrusted notebook is opened and attempts to perform dynamic evaluations.

By default, the UntrustedPath option value contains the user's desktop folder (where web browser downloads are likely to be stored), the user's configuration folder (where email attachments are likely to be stored), and the computer's temporary directory. If the user has configured his or her web browser or email program to save downloaded files in nonstandard locations, then the user is encouraged to add these locations to the UntrustedPath option value.

Here are the directories on your computer that are currently untrusted by the Wolfram Language:

Dynamic[Column[ToFileName/@CurrentValue[$FrontEnd,{"NotebookSecurityOptions","UntrustedPath"}]]]

"Edit UntrustedPath..."

Nesting

Directories in TrustedPath and UntrustedPath can be nested. A notebook is trusted if the most deeply nested directory containing the notebook is trusted. Consider the following example:

TrustByDefault

The TrustByDefault option determines whether the Wolfram Language should display an alert when the user opens notebooks with dynamic content whose containing directories are neither trusted nor untrusted. Below are the possible values for the TrustByDefault option.

Values for TrustByDefault option.

The current value of the TrustByDefault option is: NotebookSecurityOptionsTrustByDefault

Unsafe Dynamic Content

Dynamic content is considered unsafe if it:

Changing Option Values

TrustedPath, UntrustedPath, and TrustByDefault are options in the NotebookSecurityOptions category. They can be changed using the "Preferences..." dialog or the "Option Inspector...".

Any attempt to change the value of the TrustedPath, UntrustedPath, or TrustByDefault options will cause the Wolfram Language to prompt the user to confirm the change. The Wolfram Language does this as a security precaution so that malicious code cannot change the value of these options without the user's knowledge.