alert udp $HOME_NET any -> $EXTERNAL_NET 53 (msg:"ET POLICY nstx DNS Tunnel Outbound"; content:"cT"; offset:12; depth:3; content:"|00 10 00 01 00 00 29 08|"; within:255; reference:url,savannah.nongnu.org/projects/nstx/; reference:url,nstx.dereference.de/nstx; classtype:bad-unknown; sid:2002676; rev:3; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, updated_at 2019_07_26;)