alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE [ANY.RUN] DarkCrystal Rat Exfiltration (POST)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".php"; endswith; http.host; pcre:"/^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$/"; http.content_type; content:"multipart|2f|form|2d|data|3b 20|boundary|3d 2d 2d 2d 2d|"; http.header; content:"Expect|3a 20|100|2d|continue|0d 0a|"; http.header_names; content:"|0d 0a|Content-Type|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Expect|0d 0a 0d 0a|"; bsize:60; http.request_body; content:"Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|"; pcre:"/^(?:[0-9]{1})/R"; content:"|22 0d 0a|Content|2d|Type|3a 20|text|2f|plain"; within:28; content:"Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|"; pcre:"/^(?P<filename>[a-z0-9]{40})\x22\x3b\x20filename\x3d\x22(?P=filename)\x22/R"; content:"|0d 0a|Content|2d|Type|3a 20|application|2f|octet|2d|stream|0d 0a 0d 0a|UEsDB"; fast_pattern; reference:md5,ec01cff4cf0004f1b6c934d7263f5023; reference:url,app.any.run/tasks/79b78536-75bf-43b4-99d6-3438ba41e40c; reference:url,community.emergingthreats.net/t/darkcrystal-rat/952; classtype:trojan-activity; sid:2048130; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_09_20, deployment Perimeter, malware_family DCRat, confidence High, signature_severity Critical, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_09_20, reviewed_at 2023_09_20;)