""ET TROJAN Cobalt Strike Beacon Activity""

SID: 2032274

Revision: 2

Class Type: trojan-activity

Metadata: attack_target Client_Endpoint, created_at 2021_03_22, deployment Perimeter, deployment SSLDecrypt, signature_severity Major, tag c2, updated_at 2021_03_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: "/userid=" Depth: 8

  • Value: "Content-Transfer-Encoding|3a 20|base64|0d 0a|"

  • Value: !"Referer|3a 20|"

Within:

PCRE: "/\/userid=[A-Z]{256}$/U"

Special Options:

  • http_method

  • fast_pattern

  • http_uri

  • http_header

  • http_header

source