Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
3,141 detections
Filters
Last updated
All Time
Detection languages
2,292
246
196
179
104
Contributors
738
670
569
284
148
Categories
1,163
747
693
623
440
Platforms
39,936
7,266
6,537
3,866
3,647
3,141
Products / Services
2,849
742
268
187
182
MITRE Techniques
871
856
778
768
738
CVEs
13
5
2
1
1
IDS Classtypes
3
2
2
2
1
IDS Protocols
9
1
1
This rule monitors for high-frequency download or access events of files associated with AI development, such as model weights (.pt, .ckpt, .safetensors, .h5, .onnx, .pkl, .pb), checkpoints, and research datasets from cloud storage. It triggers when an account accesses or downloads 20 or more unique AI-related files within a 60-minute window, which is indicative of unauthorized data exfiltration of intellectual property.
Detects potential Business Email Compromise (BEC) by monitoring inbound email threads for unexpected changes in the sender domain during ongoing conversations. This rule flags replies that contain payment-related keywords (e.g., IBAN, SWIFT, bank details) where the sender domain has not been observed in the previous 30 days of the thread's history.
Detects known file hashes associated with SideCopy/ReverseRAT.
This rule monitors for indicators of compromise (IOCs) associated with the threat actor SideCopy and their associated malware, such as ReverseRAT. It hunts for specific malicious SHA256 file/process hashes, connections to known malicious C2 infrastructure (IPs and domains), requests to known malicious URLs, and user interaction with these URLs via email clicks.
Detects incoming email messages where the Reply-To header address domain differs from the Sender From address domain. This technique is commonly used in phishing attacks to redirect victim replies to an attacker-controlled mailbox while maintaining a spoofed appearance in the original sender field.
Detects inbound emails that have been delivered to the user's Inbox or Junk folder despite failing SPF authentication checks. The detection logic triggers when these emails also lack a valid DMARC policy (none or not available), which prevents the mail server from enforcing rejection or quarantine, allowing spoofed or unauthenticated mail to bypass standard security filters.
This rule detects potential phishing attempts where the sender's display name is formatted as an email address and the sender's domain uses a capital 'I' character to mimic a well-known service provider (typosquatting/homoglyph attack), such as 'gmaiI.com'. It identifies discrepancies between the actual sender domain and the normalized domain name after character replacement.
Detects modifications to Microsoft Exchange mailbox folder permissions where the 'Default' user is granted 'Owner' access. This activity, which may involve operations such as 'UpdateFolder', 'Add-MailboxFolderPermission', or 'Set-MailboxFolderPermission', is a known server-side persistence mechanism. By granting 'Owner' rights to the 'Default' user, an attacker can bypass standard authentication and device-level controls to access mailbox contents, often following initial exploitation such as OWA XSS.
Joins password reset events to subsequent legacy-protocol (IMAP/POP/SMTP/ActiveSync) or non-interactive sign-ins for the same user, catching attackers who pivot to less-monitored protocols immediately after a vished self-service reset.
Detects tenant-level enablement of Microsoft Teams external/federated access or addition of an unfamiliar external domain shortly before a spike in inbound Teams calls to helpdesk/IT-support-tagged users — models CrowdStrike's 2026 Financial Services Threat Landscape Report on 'Mutant Spider,' the most active threat to financial services, whose primary technique is voice phishing over Microsoft Teams impersonating internal IT.
Detects a sequence of events where a single user receives an unusually high volume of inbound emails (potentially vishing-related), followed shortly thereafter by the user executing common remote assistance or remote access tools (e.g., Quick Assist, AnyDesk). This pattern is consistent with social engineering tactics used in IT-support impersonation scams to facilitate the delivery of malware such as Sauron Loader.
This rule detects scenarios where a user account modifies Conditional Access (CA) policies (specifically targeting user or group inclusion/exclusion settings) within one hour of that same user account modifying authentication method policies. This pattern is potentially indicative of an adversary weakening security controls by adjusting authentication requirements and subsequently tampering with CA policies to maintain persistence or bypass MFA.
Single-source Sigma proxy for the authentication-persistence stage of the multi-stage device-code-phishing-to-Graph-collection chain (see the companion KQL correlation rule "Passkey Persistence: Device-Code Phishing to MFA Takeover and Graph Collection" for the full, threshold-gated, cross-table detection). Sigma has no join, temporal-windowing, or aggregation support, so this rule fires on the authentication-persistence event alone and does NOT enforce the device-code sign-in precursor or the subsequent Graph-activity burst - both required by the full correlation. Scoped to the two highest-signal operations only (new security-info registration, and any admin-initiated registration on another user's account) to cut noise from routine self-service profile edits.
Single-source Sigma proxy for the authentication-persistence stage of the multi-stage device-code-phishing-to-Graph-collection chain (see the companion KQL correlation rule "Passkey Persistence: Device-Code Phishing to MFA Takeover and Graph Collection" for the full, threshold-gated, cross-table detection). Sigma has no join, temporal-windowing, or aggregation support, so this rule fires on the authentication-persistence event alone and does NOT enforce the device-code sign-in precursor or the subsequent Graph-activity burst - both required by the full correlation. Scoped to the two highest-signal operations only (new security-info registration, and any admin-initiated registration on another user's account) to cut noise from routine self-service profile edits.
Detects the multi-stage Microsoft cloud identity compromise chain reported by Microsoft Security Research (September 2026): a victim completes a successful Entra ID device-code sign-in (often induced by passkey-themed device-code phishing), the same identity's authentication/security info is registered or changed (MFA/passkey persistence) within 60 minutes (deduplicated to the earliest such event per sign-in), followed within 120 minutes by a burst of at least 25 successful, delegated-context Microsoft Graph API calls (Scopes claim populated, i.e. user-delegated permissions rather than pure application/client-credential access) spanning at least 3 distinct resource paths, exhibiting reconnaissance (>=5 requests against /users, /groups, /directoryRoles, /roleManagement, /applications, /servicePrincipals, /organization) and/or collection (>=10 requests against /messages, /mailFolders, /attachments, /drive, /drives, /sites, /lists, /search) patterns. Restricting to delegated (Scopes-bearing) Graph calls and requiring resource-path breadth removes the two largest false-positive sources: service-principal/application-only automation jobs (Roles-only tokens) and single-endpoint polling tools. Pure behavioral correlation across SigninLogs, AuditLogs, and MicrosoftGraphActivityLogs - no static IOCs. Flags whether Graph activity originated from an IP different from the original device-code sign-in IP as a strong pivot/session-reuse indicator.
Detects instances where a user account registers a new Multi-Factor Authentication (MFA) method (such as TOTP or Authenticator app) shortly (within 30 minutes) after a high-risk or potentially anomalous sign-in event. This pattern is commonly associated with adversary-in-the-middle (AiTM) phishing attacks where an attacker captures an authenticated session and uses it to enroll a secondary, attacker-controlled MFA device for persistent account access.
Detects rapid, automated-style creation of an application, associated service principal, and delegated permission grants within a 60-second window. This behavior is indicative of the TrustSink technique or similar automated adversary infrastructure setup in Microsoft Entra ID (formerly Azure AD), where an attacker establishes persistence or elevated access through newly created apps.
This rule detects email-based phishing campaigns impersonating voicemail notifications ('New VM Received') that utilize Mailchimp click tracking to redirect recipients to landing pages hosted on the .sibpages.com domain, often associated with Brevo/Convrrt services.
Detects the creation of suspicious O365 inbox rules designed to hide (via mark-as-read, move, or delete actions) or forward/redirect email messages containing keywords associated with financial transactions such as payment, wire, or invoice. This behavior is indicative of post-compromise activity, specifically targeted at invoice fraud or email thread hijacking.
This rule monitors inbound emails for sender domains or embedded URLs that contain strings related to popular AI service brands (e.g., ChatGPT, Gemini, Claude). It flags these occurrences when the domain does not match the official, legitimate domains for those services, indicating potential phishing or brand impersonation attempts.
Detects phishing messages that deliberately mix writing systems/scripts/homoglyphs in the Subject line as ONE corroborating signal within a broader, multi-signal phishing pattern. Hardened against false positives: brand/product tokens (e.g. Microsoft, PayPal) are stripped before the Latin-script check so a lone brand mention in non-Latin correspondence doesn't count as mixed-script; the suspicious-URL signal requires a high-confidence credential/urgency term (not generic business vocabulary); sender risk requires the domain to be new to both the recipient and the organization; and at least three independent signal categories (not two) must corroborate the language-confusion signal before the rule fires.
Page 18 of 150