Extract from the piece:
"Symbian’s adoption of descriptors is but one example of what is called a “defensive” approach to software: each software component has to be ready to deal with malformed data passed to it by other components. It cannot take it for granted that the data conforms to the expected structure. This attitude is reinforced by various development tools and the general development culture in the Symbian ecosystem. As a result, I’m pleased to report that there are (as yet) no known cases of “backdoor” or “side-window” security flaws in Symbian OS. Unlike with other operating systems, malware cannot exploit buffer overflows or similar programming bugs to install itself onto a Symbian smartphone and cause damage. Instead, the only known route for malware onto a Symbian smartphone is via the “front door” – the installation dialog which requires the user’s consent to add new software into the smartphone."