Potential prompt injection attack in body HTML

 1name: "Potential prompt injection attack in body HTML"
 2description: "Detects messages containing references to major AI tools (like Gemini, Copilot, ChatGPT, or Claude) in non-standard HTML elements."
 3type: "rule"
 4severity: "high"
 5source: |
 6  type.inbound
 7  and length(filter(html.xpath(body.html, "//*[local-name() = 'admin']").nodes,
 8                    length(.display_text) > 0
 9                    and strings.ilike(.display_text,
10                                      '*gemini*',
11                                      '*copilot*',
12                                      '*chatgpt*',
13                                      '*claude*'
14                    )
15             )
16  ) > 0
17  
18  // negate highly trusted sender domains unless they fail DMARC authentication
19  and (
20    (
21      sender.email.domain.root_domain in $high_trust_sender_root_domains
22      and not headers.auth_summary.dmarc.pass
23    )
24    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
25  )  
26attack_types:
27  - "Callback Phishing"
28  - "Credential Phishing"
29  - "Extortion"
30  - "Malware/Ransomware"
31  - "Spam"
32  - "BEC/Fraud"
33tactics_and_techniques:
34  - "Evasion"
35  - "Social engineering"
36detection_methods:
37  - "Header analysis"
38  - "HTML analysis"
39  - "Content analysis"
40id: "5fb24736-df8a-5a3a-84da-a2d5560d73d1"