""ET TROJAN LNK/Unknown Downloader CnC Checkin (POST)""

SID: 2047717

Revision: 2

Class Type: trojan-activity

Metadata: affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_08_23, deployment Perimeter, deployment SSLDecrypt, signature_severity Critical, updated_at 2024_02_08, reviewed_at 2023_08_23

Reference:

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: $HTTP_PORTS

Flow: established,to_server

Contents:

  • Value: "POST"

  • Value: "Keep-Alive: 300|0d 0a|"

  • Value: "User-Agent|3a 20|Mozilla|2f|4|2e|0|20 28|compatible|3b 20|Synapse|29 0d 0a|"

  • Value: "id=" Depth: 3

  • Value: "&data="

  • Value: "&act=100"

  • Value: "Connection|3a 20|keep-alive|0d 0a|"

  • Value: "application|2f|x|2d|www|2d|form|2d|urlencoded"

Within:

PCRE: "/^Host\x3a\x20(?:[0-9]{1,3}.){3}[0-9]{1,3}$/Hm"

Special Options:

  • http_method

  • http_header

  • http_header

  • http_client_body

  • http_client_body

  • http_client_body

  • fast_pattern

  • http_header

  • http_header

source