Detections

Explore public detection logic contributed by the community across SIEM and rule languages.

3,141 detections

Detects Microsoft Graph API requests targeting user mailboxes within a tenant or organization structure likely associated with Israeli legal entities, identified by .co.il domain patterns in the Request URI.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
004
Detects suspicious modifications or deletions of Outlook calendar events using the Microsoft Graph API, potentially indicating the use of calendar infrastructure as a command-and-control (C2) heartbeat or exfiltration channel. The rule monitors for specific pattern-based event updates or deletions following calendar enumeration, which is a technique used to maintain persistent communication or exfiltrate small amounts of data.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
104
Detects Microsoft 365 Outlook calendar events being updated via Graph API where the subject is changed to a suspicious C2-like string (e.g., 'Boss Report ID:' or 'Boss update ID:'). This behavior is consistent with attackers using Outlook calendar events as a covert communication channel or for command and control signaling.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
704
Detects high-frequency authentication attempts or broad user targeting originating from scripts using the 'python-requests' library. This behavior is indicative of programmatic password spraying or automated credential stuffing attacks.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
15018
Detects instances where a user receives an email containing a link to SharePoint or OneDrive, but upon clicking the link, the user is redirected to a different, non-Microsoft domain. This behavior is indicative of a phishing attempt using legitimate file-sharing services to bypass initial URL filtering.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
19118
This rule detects scenarios where an email containing a specific URL has been soft or hard deleted from a user's mailbox (often by security automated systems), but a user has subsequently clicked that same URL. This often indicates a race condition or a failure in security controls where a malicious link was delivered and accessed before or during the removal process.
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Shadows VMB@Vemorian_Mort
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Detections.ai Community
4 months ago
25169
This rule monitors the Microsoft 365 AuditLogs to retrieve and investigate all actions taken by or against a specific user account. It expands the TargetResources field to extract the TargetUPN and filters for a specific account, providing a timeline of operations, the actor who initiated the action, and the result of the operation.
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Shadows VMB@Vemorian_Mort
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Detections.ai Community
4 months ago
3015
Detects GET requests to the Microsoft Graph API 'organization' endpoint, often used by malicious tools to validate a tenant environment or gather metadata before initiating C2 communication or secondary stages of an attack.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
002
Detects anomalous activity in Microsoft 365 calendar events where potential C2 data is exfiltrated or synchronized. This is identified by the creation or modification of calendar events containing suspicious file names (e.g., File0.txt, File1.txt) or specific command-and-control markers within the event subject.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
102
Detects anomalous access to Outlook calendar attachments via the Microsoft Graph API, specifically targeting a file named 'file0.txt'. This activity may indicate a technique where attackers use calendar events as a covert channel for data exfiltration or delivery of malicious payloads.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
002
Detects Microsoft 365 Outlook calendar events with highly anomalous future dates (specifically the year 2050) or specific subject patterns, which are indicative of a command-and-control (C2) communication channel established via calendar item properties.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
202
This rule monitors email traffic by aggregating data from email events, attachment information, and URL click interactions. It identifies emails that contain attachments and correlates them with specific file attributes (name, extension, hash, threat type) and any subsequent user interaction with URLs contained within those emails, including blocked or allowed clicks.
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Shadows VMB@Vemorian_Mort
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Detections.ai Community
4 months ago
27253
This rule detects potential phishing attempts by identifying emails that contain links to legitimate Microsoft Forms (forms.office.com) with lures commonly associated with document-related phishing (e.g., 'shared a document', 'invoice'). The rule then correlates this with user click activity to identify instances where the user was redirected from the Microsoft Forms site to an external, potentially malicious URL.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
4011
This rule detects access to known adversary-in-the-middle (AiTM) phishing infrastructure mimicking Microsoft login pages. It identifies malicious URLs matching specific randomized path token patterns or those hosting a known phishing domain, while also monitoring for associated session-specific parameters such as 'rt=', 'PHPSESSID', and 'preload=1' cookies, as well as traffic interacting with legitimate 'login.microsoftonline.com' domains in a proxy context.
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Ethan Andrews@eandrews
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Federal Signal Detections
4 months ago
22051
This rule identifies suspicious email messages that contain isolated blocks of text preceded by at least two whitespace characters (including newlines, carriage returns, or tabs). This pattern is often used by threat actors to obfuscate content, attempt to bypass email gateway filters, or hide malicious strings from security scanners by breaking up content flow.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
2011
Detects anomalous, automated data exfiltration cycles in Microsoft 365 environments consistent with the Helix threat group. The rule identifies a pattern of successful sign-ins followed within 6 hours by new MFA registration, suspicious SharePoint enumeration, and a high-frequency, non-human-paced burst of file downloads.
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Ethan Andrews@eandrews
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Federal Signal Detections
4 months ago
54048
Detects suspicious use of the OAuth 2.0 device code authentication flow. The rule identifies potential token harvesting and phishing attempts by flagging device code sign-ins that originate from unusual user agents, unknown IP addresses or ASNs, unrecognized applications, or for users who have not previously utilized device code authentication. Legitimate, first-party applications like Azure CLI and Azure PowerShell are explicitly excluded to minimize noise.
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Georgios Maragos@Gmarak
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Detections.ai Community
4 months ago
30069
This rule detects email activity where a user receives an email containing a link to 'tilda.ws' (often used for landing pages) with social engineering themes like invoices or document signing, and subsequently clicks the link to be redirected to a different destination. This pattern is indicative of a credential phishing or malicious landing page campaign.
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Duo Tech@duotech
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Detections.ai Community
4 months ago
7010
Detects new device registrations in Microsoft Entra ID where the device display name is prefixed with 'Forg365-', a pattern used by the Forg365 PhaaS (Phishing-as-a-Service) platform. This activity is indicative of an adversary establishing persistent, unmanaged device access to compromised Microsoft 365 accounts.
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Ethan Andrews@eandrews
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Federal Signal Detections
4 months ago
17037
Detects anomalous activity in Microsoft 365 calendar events where potential C2 data is exfiltrated or synchronized. This is identified by the creation or modification of calendar events containing suspicious file names (e.g., File0.txt, File1.txt) or specific command-and-control markers within the event subject.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
001
Detects suspicious modifications or deletions of Outlook calendar events using the Microsoft Graph API, potentially indicating the use of calendar infrastructure as a command-and-control (C2) heartbeat or exfiltration channel. The rule monitors for specific pattern-based event updates or deletions following calendar enumeration, which is a technique used to maintain persistent communication or exfiltrate small amounts of data.
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Duo Tech@duotech
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Detections.ai Community
3 months ago
001
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