alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE PureCrypter Requesting Injector M1"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/dl/"; fast_pattern; pcre:"/^\d{4}\/\w{2,8}_\w{8}\.bmp/R"; content:".bmp"; endswith; reference:url,blog.netlab.360.com/purecrypter/; classtype:command-and-control; sid:2038689; rev:2; metadata:created_at 2022_08_31, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_08;)