Adobe Acrobat XI - Manual (Page 372)

365
Security
Last updated 1/14/2015
No Options, Allow, or Play button?
If the warning does not contain an Options, Allow, or Play button, your administrator has disabled this feature. You
cannot choose to trust or allow this content. Click the Close or Cancel button to hide the warning. You can view the
PDF, but you cannot access any of the blocked content. Contact your administrator for more information.
Note: For a full list of articles about security, see Overview of security in Acrobat and PDF content .
When are security warnings displayed?
Security warnings can be displayed in the following situations:
Blacklisted JavaScript
JavaScript is a computer language in widespread use. JavaScript code can be vulnerable to attacks, and JavaScript can
be used to open websites. Adobe regularly updates the blacklist with known JavaScript vulnerabilities. If a PDF tries to
access blacklisted JavaScript, you see a message in the yellow document bar, at the top.
For administrators:
• For instructions on how to manage JavaScript execution, see the article JavaScripts in PDFs as a security risk
• For more information about the situations that trigger JavaScript warnings and blacklisted JavaScript, see
www.adobe.com/go/acroappsecurity .
Security settings updates
Adobe periodically distributes certificates for security purposes. These downloads help ensure that digitally signed
PDFs from trusted sources maintain their trusted status. If you receive an update from an unknown source, verify that
it is from a web address that you trust before proceeding. Updates from untrusted websites can create vulnerabilities on
your computer.
Accessing stream objects (XObjects)
Acrobat and Reader display a warning when a PDF attempts to access external content identified as a stream object.
For example, a URL might point to an external image. The silent transmission of data can pose a security risk as Acrobat
and Reader communicate with an external source.
Inserting data into PDFs and forms
A warning appears when an untrusted source attempts to add data to a PDF form. Although this data-injection feature
can streamline workflows in your organization, it can also be used to add malicious data into a PDF.
Silent printing
Silent printing is printing to a file or printer without your confirmation. It is a potential security risk because a
malicious file can silently print multiple times to your printer, wasting printer resources. It can also prevent other
documents from printing by keeping the printer busy.
Contact your system administrator to determine when to allow silent printing.
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