alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Chafer Win32/TREKX Uploading to CnC (Modified CAB)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:".aspx"; endswith; http.request_body; content:"Content-Disposition|3a 20|form-data|3b|"; content:"TREC"; distance:0; fast_pattern; pcre:"/^[\x20-\x7e\r\n]{0,13}[^\x20-\x7e\r\n]/Rs"; http.content_type; content:"multipart|2f|form-data|3b|"; http.content_len; byte_test:0,>=,256,0,string,dec; http.header_names; content:!"Referer"; reference:url,securityintelligence.com/posts/observations-of-itg07-cyber-operations/; classtype:command-and-control; sid:2027480; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_06_17, deployment Perimeter, malware_family TREKX, performance_impact Low, confidence High, signature_severity Major, tag Chafer, tag APT39, updated_at 2020_09_17;)