What is the ruling on working for a company that provides CAPTCHA services if it sells its services to abusive websites or companies?

Working in programming "captcha" codes is permissible. However, the company selling these codes to websites or companies that promote immorality is forbidden, because it involves aiding in sin. The management of the company and those directly involved in the sale bear the sin. The workers in programming or operational tasks are not sinful, because their work is originally permissible. The prohibition relates to selling it to those who use it in forbidden ways, and this is not related to their work. Therefore, there is no harm in working for the company as long as the worker is not directly involved in selling it to abusive companies.