English equivalent of the expression “a longer arm than résumé”

I've heard a non-native English speaker use the expression "in this place, having a long arm to scratch someone else's back is more important than having a long résumé", conveying the idea of favoritism in a place influencing the promotion of people within. I would like to know if there is an equivalent in English to such expression.

Solution 1:

The phrase

It's not what you know but who you know.

seems to have similar connotations, although is more about knowing the right people, than currying favour with them.

There is the more salacious

Sleep your way to the top

which takes the back scratching a little more literally.

Solution 2:

I understood your question as asking for an idiom for nepotism or sycophantic promotion.

One could say, "When it comes to promotions in this company, flattery will get you everywhere."

There's a theory on the origin of "Bob's your uncle" which is based on nepotism (although the saying doesn't mean that anymore).