libunrar library have critical error which can cause hanging with 100% cpu load. Error was found and fixed by McMCC.
1) Compile security/clamav with LIBUNRAR support
2) download file http://mcmcc.bat.ru/clamav/hz.rar
3) Check file hz.rar using clamdscan
clamd will hanf with 100% cpu load.
I'll take it.