hello,
due to the nature of crypto mining, cgminer has been used in some malware, which has caused most av's to now conclude that cgminer is malware.
The original is quite safe. just make sure that you download it from a reputable link, such as one on this forum and you should be fine. or
http://ck.kolivas.org/apps/cgminer/even if it is still detected as a virus, just add it to your exclusions in your av settings.
Thanks