Earlier this week, we realized that part of our public online Virus Encyclopedia (VE) was altered via external hacking.  The redirect placed on our site didn’t work properly so nobody visiting the hacked pages was at risk of infection.  In response to this incident, we shut down the VE for several hours, patched the systems, removed the inserted code, and brought it back to life again.  We have already taken interim measures to further harden the VE system against future attacks.  This incident was part of a wider attack on Web sites around the world.

InformationWeek, quoting Mike Sweeny, publishes a report on this incident.