alert tcp any any -> any [139,445] (msg:"ET DELETED Possible Duqu 2.0 Accessing SMB/SMB2 backdoor"; flow:to_server,established; content:"SMB"; offset:5; depth:3; content:"tttttttt"; nocase; distance:0; fast_pattern; reference:url,securelist.com/blog/research/70504/the-mystery-of-duqu-2-0-a-sophisticated-cyberespionage-actor-returns/; classtype:trojan-activity; sid:2021243; rev:1; metadata:created_at 2015_06_10, signature_severity Unknown, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)