QOTD on Custom Malware

Every network we monitor, every large customer, has some kind of customized malware infiltrating data somewhere. I imagine anybody in the global 2,500 has this problem.
[...]
It's fairly trivial to customize an exploit to bypass 70 percent of the time. I do it all of the time on engagements.

-- Shawn Moyer, managing principal at security services firm Accuvant Labs

Src: Customized, stealthy malware growing pervasive - CSO Online - Security and Risk