""ET INFO Observed Cloudflare DNS over HTTPS Domain (cloudflare-dns .com in TLS SNI)""

SID: 2027695

Revision: 4

Class Type: misc-activity

Metadata: affected_product Any, attack_target Client_Endpoint, created_at 2019_07_09, deployment Perimeter, performance_impact Low, signature_severity Informational, tag DoH, updated_at 2023_10_05, reviewed_at 2024_04_22

Reference:

Protocol: tcp

Source Network: $HOME_NET

Source Port: any

Destination Network: $EXTERNAL_NET

Destination Port: 443

Flow: established,to_server

Contents:

  • Value: "|16|"

  • Value: "|01|"

  • Value: "|00 00|"

  • Value: "|00|"

  • Value: "cloudflare-dns.com"

Within: 1

PCRE: "/^(?:\x00\x12|.\x2e)cloudflare-dns.com/R"

Special Options:

source