We have received reports from multiple bMail users who received messages earlier this morning from Mail Delivery Subsystem which stated messages sent from them had been rejected for potential security issues.
If you received such a message, simply delete it. Your account has not been hacked. The original message was forged, and did not come from your account. Since the original contained a virus, Google is rejecting it and sending the mailer-daemon to you.
The original message was received at Tue, 28 Jun 2016 09:19:36 -0700
from ees-ppworker-prod-04.ist.berkeley.edu [169.229.218.210]
----- The following addresses had permanent fatal errors -----
(reason: 552-5.7.0 This message was blocked because its content presents a potential)
(expanded from: <oski@berkeley.edu>)
----- Transcript of session follows -----
... while talking to aspmx.l.google.com.:
>>> DATA
<<< 552-5.7.0 This message was blocked because its content presents a potential
<<< 552-5.7.0 security issue. Please visit
<<< 552-5.7.0 https://support.google.com/mail/answer/6590 to review our message
<<< 552 5.7.0 content and attachment content guidelines. be4si34285138pab.223 - gsmtp
554 5.0.0 Service unavailable
Final-Recipient: RFC822; oski@berkeley.edu
X-Actual-Recipient: RFC822; oski@g.berkeley.edu
Action: failed
Status: 5.7.0
Remote-MTA: DNS; aspmx.l.google.com
Diagnostic-Code: SMTP; 552-5.7.0 This message was blocked because its content presents a potential
Last-Attempt-Date: Tue, 28 Jun 2016 09:19:36 -0700