I have a full page visa and entrance stamps from Sudan in my passport, and I've crossed into the US three times now with that in my passport and they've never said a word.
Seems you're not eligible to a Visa Waiver if you traveled to Iran or Sudan. Which means you need to apply for a visa at your US embassy [1] (which in my case was expensive and required a one day trip). Also it's not only a matter of having an Iranian stamp on your passport. You're not eligible for the VWP even if you visited this countries. I wouldn't try to lie about this!
"When can’t I use the VWP (ESTA) and need a visa?
Due to personal circumstances:
you traveled to certain countries (Iran, Iraq, Sudan, Syria, Libya, Somalia, and Yemen on or after March 1, 2011)"
I think the issue is that Sudan has a very different dynamic with the US with respect to military intelligence/affairs. I don't really think Sudan is considered a sophisticated threat at the moment.
"When can’t I use the VWP (ESTA) and need a visa?
Due to personal circumstances:
you traveled to certain countries (Iran, Iraq, Sudan, Syria, Libya, Somalia, and Yemen on or after March 1, 2011)"
[1] https://nl.usembassy.gov/visas/visa-waiver-program/