alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Corebot Module Download"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".exx"; endswith; http.user_agent; content:"Mozilla/5.0 (Windows NT 6.1|3b 20|rv|3a|15.0) Gecko/20100101 Firefox/15.0.1"; fast_pattern; startswith; http.header_names; content:!"Content-Type|0d 0a|"; content:!"Accept"; reference:url,securityintelligence.com/watch-out-for-corebot-new-stealer-in-the-wild/; reference:md5,f7dff17acec6b79f3cdad6259cfb2d2c; classtype:trojan-activity; sid:2021742; rev:3; metadata:created_at 2015_09_01, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_06_01;)