CGI漏洞(5) input, so any program based on jj.c could potentially be exploited by simply adding a followed by a Unix command. It may require a passWord, but two known passwords include HTTPdrocks and SDGROCKS. If you can retrieve a copy of the compiled program running strings on it will probably reveil the password.
Do a web search on jj.c to get a copy and study the code yourself if you have more questions.