Near as I can find, any reference in SR3 to defaulting to an Attribute is described for when the needed Skill is not in the PCs list of Skills.

In SR3, is it possible to default to an Attribute from a Skill that has a low Rating currently? Say, Skill at 1 but associated Attribute at 8 might be a reasonable default even with the +4 to target number.

If it is possible, is there a reference in the books?

There's defaulting from skill to skill and from skill to specialization, but only in the same group of skills, such as using Edged Weapons or a (Swords) specialization in place of Clubs, but this is also only possible if you don't have the Clubs skill in this example.
Rules for that are on p. 84.

In short: Once you got the skill, you gotta use the skill. On the bright side, you gain access to the full applicable pool once you have the skill, or half pools if defaulting to skills / specs.

You can also use Karma Pool to add extra dice.

Bye
Thanee