DNA could be intact, but there's still the problem of cosmic ray bombardment. Some probably good DNA has been extracted from some very old termites in amber. Abstract here. While the DNA had generally been shot up badly, a recognizeable fragment coding for ribosomes was isolated and studied.
GEEZ! Always something. Did some snooping around to learn a little about cosmic rays; found this interesting piece from HERE:
What happens when they hit earth?
The combined energy of all the cosmic rays approaching Earth is massive. Fortunately the atmosphere and magnetosphere [§] protect us from them as effectively as a slab of concrete four metres thick. Even so, when cosmic rays collide with atoms in the upper atmosphere, they release showers of gamma rays, X-rays and subatomic particles. Most of these secondary particles will make it to the Earths surface. And the most energetic fragments, although rare, are capable of penetrating miles underground. 
Atomic structures mainly consist of space - space between the nucleus and electrons, space between the individual atoms. Because of this, sub-atomic particles can travel a great distance before they collide with anything. Consequently most cosmic rays and secondary particles pass right through houses, trees, rocks, birds and humans. But a few will occasionally crash into atoms within these structures and beings. Dont be too alarmed; this cosmic radiation is minor compared to the Earths natural background radiation, which in total hardly affects any of us at all anyway.
Thousands of rays and fragments pass through our bodies every minute.  Outside of the Earths atmosphere, where some satellites and astronauts roam, cosmic rays are very dangerous indeed - their sheer frequency means they can ionise electronic circuitry and mutate the genes of astronauts.
Now, what I found interesting is the author, at least in this snippet, said the actual cosmic rays never make it through our atmosphere(only acting as a super collider it seems), but then goes on to consistantly discuss them as if they do make it this far. Color me more confused!
In any case, my point was that it would seem that DNA is being extracted from something other than these extremely rare hermetically sealed fossils. That is, they are able to extract DNA from what is essentially........rock?
So did I miss something?