""ET CURRENT_EVENTS [Fireeye] Backdoor.HTTP.BEACON.[Yelp GET]""

SID: 2031280

Revision: 3

Class Type: trojan-activity

Metadata: affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_12_08, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_12_09, 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: "request_origin=user"

  • Value: "|0d 0a|Sec-Fetch-Dest|3a 20|empty|0d 0a|"

  • Value: "GET|20|" Depth: 4

  • Value: "&parent_request_id="

  • Value: "|20|HTTP/1"

Within: 1024

PCRE: "/^GET [^\r\n]{0,256}&parent_request_id=(?:[A-Za-z0-9_\/+-%]{128,1024})={0,2}[^\r\n]{0,256} HTTP\/1.[01]/"

Special Options:

  • http_header

  • fast_pattern

source