alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DonotGroup Maldoc Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/"; startswith; content:"/"; distance:16; within:1; content:".mp3"; distance:48; within:4; endswith; fast_pattern; bsize:70; pcre:"/^\/[A-Za-z0-9]{16}\/[A-Za-z0-9]{48}\.mp3$/"; http.user_agent; content:!"Linux"; http.header_names; content:"|0d 0a|Accept|0d 0a|Accept-Encoding|0d 0a|User-Agent|0d 0a|Host|0d 0a|Connection|0d 0a 0d 0a|"; bsize:59; reference:md5,92a78894568e2e7869ef7ec454c52db3; classtype:trojan-activity; sid:2037126; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_06_27, deployment Perimeter, malware_family DonotGroup, performance_impact Moderate, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_06_27;)