A proliferation of banner ads apparently placed by criminal gangs looking for programmers to help make existing malware stealthier and more feature-rich. Many of the ads highlight job openings for coders who are skilled in devising custom crypters, programs designed to change the appearance of known malware so that it goes undetected by anti-virus software. The ads lead to a sign-up page where interested coders can leave their rsum and contact information, and state why they think they are qualified for the position.”]
Source: https://krebsonsecurity.com/2011/06/criminal-classifieds-malware-writers-wanted/