""ET TROJAN Tendrit CnC Beacon 1""

SID: 2019985

Revision: 1

Class Type: trojan-activity

Metadata: attack_target Client_Endpoint, created_at 2014_12_22, deployment Perimeter, signature_severity Major, tag c2, updated_at 2014_12_22, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel

Reference:

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: $HTTP_PORTS

Flow: established,to_server

Contents:

  • Value: "GET"

  • Value: "/css.ashx?" Depth: 10

  • Value: !"Referer|3a|"

Within:

PCRE: "/^\/css.ashx\?[a-z]{2,}=(?:%[A-F0-9]{2})+&/I"

Special Options:

  • http_method

  • http_uri

  • http_header

source