Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
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Detects Direct Send spearphishing impersonating internal roles (IT/Finance/Procurement) with business-themed lures targeting leadership/finance titles. Rewritten: removed a non-functional sender/recipient substring check and a broken EmailPostDeliveryEvents join that made the rule rarely fire; anchored detection to the actual Direct Send signature (null envelope + domain match) and a direct IdentityInfo join; standardized auth-failure parsing to match the other rules in this set.
Detects incoming emails where the SMTP envelope sender (MAIL FROM) is blank, but the visible 'From' header displays an internal/accepted domain. This technique is often used to bypass email authentication filters. The rule specifically alerts on cases where SPF, DKIM, or DMARC checks failed or returned 'none', yet the message was still delivered to an inbox or folder, suggesting a configuration gap or allow-list override.
Detects the delivery of .mobileconfig files or related configuration profile types (e.g., .plist, .xml) via email. These profiles are used on macOS and iOS devices to modify system settings, such as mail, calendar, or contact synchronization, and can be used to install malicious root certificates to enable Man-in-the-Middle (MITM) attacks. This rule accounts for direct attachments as well as those concealed within zip archives.
Detects a sequence of events starting with a device code OAuth sign-in, followed within two hours by the creation or modification of inbox rules and high-frequency enumeration of email items (contacts, folders, messages, threads, people) via Microsoft Graph API. This behavior is indicative of post-compromise activity where an adversary uses OAuth device code grants to maintain access and subsequently automates inbox analysis or data harvesting.
This rule detects a correlation between an email phishing burst (high volume of emails with a specific failed payment subject) and the subsequent creation of suspicious 'x_trace_' files in 'var/report/' directories. This pattern is indicative of a phishing campaign where a malicious attachment or link might be attempting to write local tracking or diagnostic files on a victim's host.
This rule detects a correlation between an email phishing burst (high volume of emails with a specific failed payment subject) and the subsequent creation of suspicious 'x_trace_' files in 'var/report/' directories. This pattern is indicative of a phishing campaign where a malicious attachment or link might be attempting to write local tracking or diagnostic files on a victim's host.
Detects anomalous email access patterns across multiple mailboxes using specific application identifiers or access contexts often associated with automated collection tools. This rule flags when an application accesses more than 20 items across distinct mailboxes in a 15-minute window, which is indicative of potential unauthorized bulk email collection or data exfiltration.
Detects Direct Send spearphishing impersonating internal roles (IT/Finance/Procurement) with business-themed lures targeting leadership/finance titles. Rewritten: removed a non-functional sender/recipient substring check and a broken EmailPostDeliveryEvents join that made the rule rarely fire; anchored detection to the actual Direct Send signature (null envelope + domain match) and a direct IdentityInfo join; standardized auth-failure parsing to match the other rules in this set.
Detects SCL-9 (high-confidence phishing/spam) messages that still reach an inbox, indicating an allow-list or transport-rule override, and enriches with any recent tenant mail-flow admin changes. Rewritten: removed a no-op self-join on EmailEvents and a broken exact-match join against CloudAppEvents' raw audit blob (was comparing a sender address against a whole JSON record and would never match); now excludes messages later auto-remediated (e.g. ZAP-quarantined) via the native LatestDeliveryLocation field, and correlates admin rule/allow-list changes via substring match over a cross join.
Detects SCL-9 (high-confidence phishing/spam) messages that still reach an inbox, indicating an allow-list or transport-rule override, and enriches with any recent tenant mail-flow admin changes. Rewritten: removed a no-op self-join on EmailEvents and a broken exact-match join against CloudAppEvents' raw audit blob (was comparing a sender address against a whole JSON record and would never match); now excludes messages later auto-remediated (e.g. ZAP-quarantined) via the native LatestDeliveryLocation field, and correlates admin rule/allow-list changes via substring match over a cross join.
Audits Direct Send traffic against an approved-IP watchlist, flagging unauthenticated inbound mail spoofing an internal domain from an unrecognized source IP. Fixed: RecipientDomain/SenderFromDomain were referenced but never defined (would have errored at runtime); replaced with derived SenderDomain/RecipientDomain consistent with the sibling rules. Removed a noisy display-name-contains-domain OR-branch. Replaced an always-true-in-practice auth check (required every one of SPF/DKIM/DMARC to show literal "Pass", which fails for many legitimate senders that pass via alignment on only one protocol) with the same CompAuth/all-three-fail logic used elsewhere in this set.
Audits Direct Send traffic against an approved-IP watchlist, flagging unauthenticated inbound mail spoofing an internal domain from an unrecognized source IP. Fixed: RecipientDomain/SenderFromDomain were referenced but never defined (would have errored at runtime); replaced with derived SenderDomain/RecipientDomain consistent with the sibling rules. Removed a noisy display-name-contains-domain OR-branch. Replaced an always-true-in-practice auth check (required every one of SPF/DKIM/DMARC to show literal "Pass", which fails for many legitimate senders that pass via alignment on only one protocol) with the same CompAuth/all-three-fail logic used elsewhere in this set.
Audits Direct Send traffic against an approved-IP watchlist, flagging unauthenticated inbound mail spoofing an internal domain from an unrecognized source IP. Fixed: RecipientDomain/SenderFromDomain were referenced but never defined (would have errored at runtime); replaced with derived SenderDomain/RecipientDomain consistent with the sibling rules. Removed a noisy display-name-contains-domain OR-branch. Replaced an always-true-in-practice auth check (required every one of SPF/DKIM/DMARC to show literal "Pass", which fails for many legitimate senders that pass via alignment on only one protocol) with the same CompAuth/all-three-fail logic used elsewhere in this set.
Detects the RejectDirectSend bypass (null SMTP envelope sender + internal-domain spoof). Tightened to require Microsoft's composite auth verdict OR all of SPF/DKIM/DMARC failing (vs. any one), excludes known-approved Direct Send relay IPs, and excludes likely-legitimate bulk/newsletter traffic via BulkComplaintLevel.
Detects inbound emails where the sender domain mimics finance-themed brands (using a regex-based pattern) and includes URLs redirecting through the ActiveCampaign platform tracking domains (activehosted.com or acemlnd.com). This rule identifies potential phishing campaigns attempting to use legitimate email marketing infrastructure to bypass reputation-based filters.
Detects high-volume internal email campaigns that exhibit characteristics of phishing, specifically utilizing sender display name impersonation of executive or IT support roles, urgent subject lines, and URLs identified as malicious by threat intelligence. The rule tracks common attributes like SPF/DKIM/DMARC failures and rapid delivery to multiple recipients.
This rule monitors for email events where the email is flagged for suspicious properties (SPF/DKIM/DMARC failure, threat categorization) and includes potentially malicious attachments or URLs. It then correlates these suspicious emails with subsequent process execution events on the recipient's endpoint within a 30-minute window, identifying a potential successful execution of a phishing payload.
This rule detects potential phishing activity by correlating email delivery events and URL click events against a set of known malicious domains and suspicious URL paths. It identifies when a user receives an email containing a suspicious link or interacts with such a link, providing visibility into potential credential harvesting or malware delivery attempts.
This rule detects potential phishing activity by correlating email delivery events and URL click events against a set of known malicious domains and suspicious URL paths. It identifies when a user receives an email containing a suspicious link or interacts with such a link, providing visibility into potential credential harvesting or malware delivery attempts.
This rule monitors for email events where the email is flagged for suspicious properties (SPF/DKIM/DMARC failure, threat categorization) and includes potentially malicious attachments or URLs. It then correlates these suspicious emails with subsequent process execution events on the recipient's endpoint within a 30-minute window, identifying a potential successful execution of a phishing payload.
This rule identifies potential phishing emails that impersonate OneDrive sharing notifications. It correlates email messages containing keywords typically associated with document sharing (e.g., 'OneDrive', 'shared', 'file') with subsequent user URL clicks. Crucially, the rule filters for clicks to domains that are not explicitly related to legitimate OneDrive, SharePoint, or 1drv.ms hosting, indicating a potential attempt to lure users to a malicious third-party site under the guise of file sharing.
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