alert tcp $HTTP_SERVERS any -> $EXTERNAL_NET any (msg:"ET ATTACK_RESPONSE Output of id command from HTTP server"; flow:established; content:"uid="; pcre:"/^\d+[^\r\n\s]+/R"; content:" gid="; within:5; pcre:"/^\d+[^\r\n\s]+/R"; content:" groups="; within:8; classtype:bad-unknown; sid:2019284; rev:3; metadata:created_at 2014_09_26, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)