These are virus PDFs. The From: field is spoofed so they are not coming from a Shenandoah University e-mail account.
Our Information Security Officer has adjusted our filter to block these e-mails, empty body with a PDF attachment.
If you opened the PDF please check what version of Acrobat you are using. The virus exploits "Unspecified vulnerability in Adobe Reader and Acrobat 8.x before 8.2.1 and 9.x before 9.3.1". If you are running one of the vulnerable versions of Adobe please let the Help Desk know and we will have your system scanned.
The best practice is to NOT open attachments from unexpected/unsolicited e-mails. Macs using "Preview" to open the PDF are not vulnerable to this attack.