>> reporter: one option on the table, tougher sanctions. north korea could be crippled if the u.s. goes after chinese banks that do business with pyongyang. or the u.s. could flex its cybermuscles and launch a counterattack on pyongyang's computer systems. >> right now the north koreans feel they're winning. the only way we'll stop them is if they were persuaded this was a bad idea. so we have got to react in a way that deters computer attacks of this kind. >> reporter: there is also a legal action, returning an indictment like the u.s. did against five chinese military hackers earlier this year. but sources tell cnn there is not enough evidence yet to tie the sony hack to specific individuals. as washington scrambles to figure out an appropriate response, one former homeland security official warns this remarkable decision to pull the film is a serious mistake. >> there are a lot of countries that would like to sensor americans. and if we start giving into it, there won't be an end to it. >> again, that was pamela brown