Everytime when I’m speaking in the conference about software security, I always emphasized that no software is 100% safe. Except you are write a "Hello World" application. Today, I come across a article in CNN which they interview a hacker in China who claim that peoples are paying him to attack the world-wide sites.
"No Web site is one hundred percent safe. There are Web sites with high-level security, but there is always a weakness," says Xiao Chen, the leader of this group.
I totally agree with the statement above. A program is just a set of instruction. A programmer who know the underlying logic always can find a opportunity to attack.
You can view the interview video from CNN below