""ET USER_AGENTS Observed Malicious User-Agent (CobaltStrike)""

SID: 2035537

Revision: 1

Class Type: trojan-activity

Metadata: attack_target Client_Endpoint, created_at 2022_03_18, deployment Perimeter, malware_family Cobalt_Strike, signature_severity Major, updated_at 2022_03_18, reviewed_at 2024_05_07, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation

Reference:

  • md5

  • b8b7a10dcc0dad157191620b5d4e5312

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: $HTTP_PORTS

Flow: to_server,established

Contents:

  • Value: "User-Agent|3a 20|Mozilla/5.0_Frsg_stredf_o21_crown_type"

Within:

PCRE:

Special Options:

  • fast_pattern

  • http_header

source