alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Gamut Spambot Checkin Response"; flow:established,to_client; flowbits:isset,ETGamut; file.data; content:"count_threads|09 09 09 3d 09|"; startswith; fast_pattern; content:"|0a|efficiency_limit|09 09 3d 09|"; distance:1; within:22; reference:url,www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/gamut-spambot-analysis; reference:md5,f00f3f47062646f900aa327b1d5ca3a1; classtype:command-and-control; sid:2018246; rev:6; metadata:created_at 2014_03_11, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_14;)