Sometimes malware protection software works too well. I found some emails with malicious executables, disguised as pdf files, in the attachment in my junk-mail folder. Unfortunately the anti-malware system removed the attachments and replaced them by the filename.
Some weeks ago a new kind of malware that resides solely in the registry was in the news. To implant Poweliks attackers must exploit a vulnerability of the system and, the good faith of the users. Pdf or rtf documents with embedded malicious code are used very often to start the attack.
Just why is the Adobe Reader such a popular tool for attackers?
Adobe Reader is very popular for viewing of pdf documents, and very notorious for its vulnerabilities. The list of known vulnerabilities published in the National Vulnerability Database is really long, and some of them are perfectly suited to implant malware. By the way, Adobe Flash Player is as popular as the Adobe Reader for attackers, and the list of vulnerabilities is of comparable size.
Fortunately advanced security options like a sandbox are available to defend malicious attacks, but these are not activated during a standard installation. Even for enterprise users the standard installation procedure must be pre-configured.
I can’t find a reason why Adobe does not install the Reader with advanced security options enabled by default. Apparently, Adobe is not interested in protecting the privacy and security of their customers.
Fortunately the National Checklist Program Repository provides ‘detailed low level guidance on setting the security configuration of operating systems and applications’.
For Acrobat Reader X a checklist is available which could be easily adapted to the Acrobat Reader XI. Although this checklist is meant for pre-configuring installation packages the configuration hints could be used to secure existing installations as well:
Navigate to menu Edit/Preferences.
In category General section Application Startup activate option Use only certified plug-ins.
In category Security (Enhanced) set the protection options as described below:
 Enable sandboxing for all files
 Enable Enhanced Security
 Disable all Privileged Locations.
Although this sounds somewhat paranoid viewing of pdf files is much more secure now. A pdf file is now opened in a sandbox running at the lowest integrity level. Most features are disabled by default, but could be enabled with just one click.