sublimemediumRule

Link: Numeric IP obfuscation in URL

Detects inbound messages containing links where the host is a numeric-only IP representation, commonly used to bypass domain-based URL filtering.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1204.002 T1486 T1036 T1027

defense-evasion

Detection Query

type.inbound
and any(body.links,
        any(.href_url.ip.translation.encoders,
            . in ('octal', 'decimal_integer')
        )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Link: Numeric IP obfuscation in URL"
description: "Detects inbound messages containing links where the host is a numeric-only IP representation, commonly used to bypass domain-based URL filtering."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(body.links,
          any(.href_url.ip.translation.encoders,
              . in ('octal', 'decimal_integer')
          )
  )
attack_types:
  - "Credential Phishing"
  - "Malware/Ransomware"
tactics_and_techniques:
  - "Evasion"
detection_methods:
  - "URL analysis"
id: "7d639d89-02ee-5729-8d6d-67a963fa5861"