And another one in the same direction:

The most determined cyber criminals don't necessarily work fast when they breach a network, and their infiltration is often silent and undetectable. But it's this brand of "low and slow" targeted attack that can also be the most deadly, security experts say:;jsessionid=UFNEPFUNCGARMQSNDLPSKH0CJUNN2JVN?articleID=212701434

Have alook also at the following blogpost about Microsoft SIR: