Detection rules › Sublime MQL
Potential prompt injection attack in body HTML
Detects messages containing references to major AI tools (like Gemini, Copilot, ChatGPT, or Claude) in non-standard HTML elements.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | Callback Phishing, Credential Phishing, Extortion, Malware/Ransomware, Spam, BEC/Fraud |
| Tactics and techniques | Evasion, Social engineering |
Event coverage
| Message attribute |
|---|
| body |
| headers.auth_summary |
| sender.email |
| type |
Rule body MQL
type.inbound
and length(filter(html.xpath(body.html, "//*[local-name() = 'admin']").nodes,
length(.display_text) > 0
and strings.ilike(.display_text,
'*gemini*',
'*copilot*',
'*chatgpt*',
'*claude*'
)
)
) > 0
// negate highly trusted sender domains unless they fail DMARC authentication
and (
(
sender.email.domain.root_domain in $high_trust_sender_root_domains
and not headers.auth_summary.dmarc.pass
)
or sender.email.domain.root_domain not in $high_trust_sender_root_domains
)
Detection logic
Scope: inbound message.
Detects messages containing references to major AI tools (like Gemini, Copilot, ChatGPT, or Claude) in non-standard HTML elements.
- inbound message
- length(filter(html.xpath(body.html, "//*[local-name() = 'admin']").nodes, length(.display_text) > 0 and strings.ilike(.display_text, '*gemini*', '*copilot*', '*chatgpt*', '*claude*'))) > 0
any of:
all of:
- sender.email.domain.root_domain in $high_trust_sender_root_domains
not:
- headers.auth_summary.dmarc.pass
- sender.email.domain.root_domain not in $high_trust_sender_root_domains
Inspects: body.html, headers.auth_summary.dmarc.pass, sender.email.domain.root_domain, type.inbound. Sensors: html.xpath, strings.ilike. Reference lists: $high_trust_sender_root_domains.
Indicators matched (4)
| Field | Match | Value |
|---|---|---|
strings.ilike | substring | *gemini* |
strings.ilike | substring | *copilot* |
strings.ilike | substring | *chatgpt* |
strings.ilike | substring | *claude* |