Am I sinful for working as an intern programmer in a company, where my general programs benefit from the company's programs, knowing that a small percentage (less than 5%) of the company's programs are directed to usurious banks, and must I search for another job or give out a portion of my salary if my work involves something unlawful?

His work is not judged unlawful as long as his work programs are general to all the company's programs, and do not directly relate to programs designated for usurious transactions or banks, and as long as the proportion of usurious programs produced by his company is very small.

Therefore, he is not obliged to seek another job unless his work requires him to design programs specifically for usurious transactions, for this is not permissible.

It is permissible for him, out of precaution and piety, to donate a portion of his salary, or to seek another job free from any suspicion.