ELF virus engineering challenges

The design phase of an ELF virus may be considered an artistic endeavor, requiring creative thinking and clever constructs; many passionate coders will agree with this. Meanwhile, it is a great engineering challenge that exceeds the regular conventions of programming, requiring the developer to think outside conventional paradigms and to manipulate the code, data, and environment into behaving a certain way. At one point in time, I did a security assessment at a large antivirus (AV) company for one of their products. While talking with the developers of the AV software, I was amazed that next to none of them had any real idea of how to engineer a virus, let alone design any real heuristics for identifying them (other than signatures). The truth is that virus writing is difficult, and requires serious skill. There are a number of challenges that come into play when engineering them, and before we discuss the engineering components, let's look at what some...