Following keywords can be used for matching on fields in headers and payloads of DCERPC packets over UDP, TCP and SMB.
Match on the value of the interface UUID in a DCERPC header. If any_frag option is given, the match shall be done on all fragments. If it's not, the match shall only happen on the first fragment.
The format of the keyword:
dcerpc.iface:<uuid>;
dcerpc.iface:<uuid>,[>,<,!,=]<iface_version>;
dcerpc.iface:<uuid>,any_frag;
dcerpc.iface:<uuid>,[>,<,!,=]<iface_version>,any_frag;
Examples:
dcerpc.iface:367abb81-9844-35f1-ad32-98f038001003;
dcerpc.iface:367abb81-9844-35f1-ad32-98f038001003,!10;
dcerpc.iface:367abb81-9844-35f1-ad32-98f038001003,any_frag;
dcerpc.iface:367abb81-9844-35f1-ad32-98f038001003,>1,any_frag;
ET Open rule example:
alert tcp any any -> $HOME_NET any (msg:"ET NETBIOS DCERPC WMI Remote Process Execution"; flow:to_server,established; dce_iface:00000143-0000-0000-c000-000000000046; classtype:bad-unknown; sid:2027167; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_04_09, deployment Internal, former_category NETBIOS, signature_severity Informational, updated_at 2019_04_09;)
Match on one or many operation numbers and/or operation number range within the interface in a DCERPC header.
The format of the keyword:
dcerpc.opnum:<u16>;
dcerpc.opnum:[>,<,!,=]<u16>;
dcerpc.opnum:<u16>,<u16>,<u16>....;
dcerpc.opnum:<u16>-<u16>;
Examples:
dcerpc.opnum:15;
dcerpc.opnum:>10;
dcerpc.opnum:12,24,62,61;
dcerpc.opnum:12,18-24,5;
dcerpc.opnum:12-14,12,121,62-78;
Match on the stub data in a given DCERPC packet. It is a 'sticky buffer'.
Example:
dcerpc.stub_data; content:"123456";
More information on the protocol can be found here: