Crypters are software tools that use a combination of encryption, obfuscation, and code manipulation of malware to make them FUD (Fully Undetectable) by legacy security products.
To understand the role that crypters play in cybercrime, it’s helpful to try to understand the cybercriminal mindset. The Holy Grail for cybercriminals is fully undetectable malware that would allow them to use the same malware repeatedly without being detected by a security solution. They also want their attacks randomized to make sure that the failure of one attack won’t affect the outcome of attacks against other victims.
more here...........http://researchcenter.paloaltonetworks.com/2015/02/examining-cybercrime-underground-part-1-crypters/
To understand the role that crypters play in cybercrime, it’s helpful to try to understand the cybercriminal mindset. The Holy Grail for cybercriminals is fully undetectable malware that would allow them to use the same malware repeatedly without being detected by a security solution. They also want their attacks randomized to make sure that the failure of one attack won’t affect the outcome of attacks against other victims.
more here...........http://researchcenter.paloaltonetworks.com/2015/02/examining-cybercrime-underground-part-1-crypters/