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Merged
merged 5 commits into from
Nov 4, 2025
Merged

Create attachment_ics_non-gregorian.yml #3444

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cb758be
Create attachment_ics_non-gregorian.yml
zoomequipd Oct 30, 2025
ebda419
Auto add rule ID
Oct 30, 2025
7ee1ba1
Update attachment_ics_non-gregorian.yml
zoomequipd Oct 31, 2025
3f597c8
Update attachment_ics_non-gregorian.yml
zoomequipd Nov 4, 2025
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Update attachment_ics_non-gregorian.yml
zoomequipd Nov 4, 2025
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21 changes: 21 additions & 0 deletions detection-rules/attachment_ics_non-gregorian.yml
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name: "Attachment: ICS file with non-Gregorian calendar scale"
description: "Detects ICS calendar attachments that use a non-standard calendar scale other than GREGORIAN, which may indicate malicious calendar files attempting to exploit calendar parsing vulnerabilities or bypass security filters."
type: "rule"
severity: "medium"
source: |
type.inbound
and any(attachments,
(
.file_extension in~ ('ics')
or .content_type in ("application/ics", "text/calendar")
)
and not strings.icontains(beta.file.parse_ics(.).scale, 'GREGORIAN')
)
attack_types:
- "Credential Phishing"
tactics_and_techniques:
- "Evasion"
detection_methods:
- "File analysis"
- "Content analysis"
id: "9315bbf5-c710-5ead-8a8e-5c7f8fb118dc"
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