Question: There is a website or store, based in Asia or Eastern Europe, that offers computer software at substantial discounts, sometimes 10% of the retail value. Can I buy from them?

Answer: There is a good chance that the software they are selling is pirated. [Often their products are presented as OEM software – which will be addressed separately, be"H.]

According to the majority opinion that halacha recognizes ownership of intellectual property, the pirated software is considered stolen property. The fact that the site is readily available to all and that many others customers purchase from it, does not permit you to purchase and use a pirated copy.  

However, according to the minority opinion that halacha does not recognize ownership of intellectual property, the primary halachic concern is one of hasagas gevul (encroachment). One could possibly argue that since the website or store sells freely on a regular basis, your individual purchase does not impact the company's revenues. The application of dina d'malchusa and minhag hamedina is also suspect in these places. Nonetheless, it is clearly considered something very improper even according to this opinion.

(See Emek Hamishpat, Zechuyos Yoztrim, Intro. 11:17; ch. 19:214)