Chkrootkit for a quick scan that the system doesn't appear to be compromised
Try below steps:
cd /usr/local/src
wget ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.tar.gz
wget wget ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.md5
md5sum -c chkrootkit.md5
tar -zxvf chkrootkit.tar.gz
cd chkrootkit-*/
make sense
./chkrootkit
cd ..