News today that an independent security researcher, Alex Wheeler, has discovered security "bugs" in Symantec (Norton Antivirus), Trend Micro (PC-cillin), F-Secure, and Sophos antivirus products, which account for more than 75% of the worldwide anti-virus software market.  
  All of the bugs allowed memory corruption on the computer, which causes a "buffer overflow", and can allow an attacker to completely control the program, and to subsequently execute other commands, with the same privileges as the antivirus program had, which are roughly equivalent to full, administrative access to the machine.  
  Wheeler revealed these discoveries at this summer's "Black Hat Briefings" in Las Vegas, an annual gathering of security experts, hackers, and geeky gurus.  Wheeler listed a frightening plethora of bad stuff that a hacker could do to one's computer via these avenues of attack, and noted that, "I think we're just scratching the surface with antivirus flaws, right now".  
  On the positive side, antivirus vendors are quick to patch or circumvent these flaws with new software releases, and the existence of such a "bug" is less alarming than is the discovery of definite exploits of the flaws, "in the wild".  The lesson for today's sermon:  Update frequently (daily), seek and apply patches (daily), and know what "normal" looks like, on your computer.  If it's doing something strange that you did not want it to do, power it off and call an expert!