Detections

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

4,259 detections

This rule detects when an SNMP OID request is made to an OpenCanary honeypot's SNMP service. This indicates an adversary is likely performing reconnaissance to gather information about the network or devices, potentially looking for vulnerabilities or sensitive data.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
0023
This rule detects when a single user generates an excessive number of 'Permission Denied' events within a one-hour timeframe in Google Cloud Platform (GCP). Specifically, it looks for more than 5 'BLOCK' actions with a severity of 'ERROR' and a status code of '7' (which typically indicates 'Permission Denied' in GCP API errors) from a single user. Additionally, it requires these events to span across more than one target application and more than one product event type, which helps to reduce false positives by indicating broader activity rather than a single, isolated error.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
3085
Detects the creation of new files with the ".evtx" extension in non-common or non-standard locations. This could indicate tampering with default EVTX locations to evade security controls or exfiltration of event logs to search for sensitive information. Note that backup software and legitimate administrators might perform similar actions during troubleshooting.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
0020
This rule detects when an Entra ID application has a significant increase in the number of assigned permissions within a short timeframe (5 minutes). This could indicate a "greedy permission grab" by an attacker attempting to escalate privileges or gain broader access to resources. The rule specifically looks for an increase of more than 8 permissions compared to the previous state. It does not compare the specific permissions, only the count.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1062
This rule detects an excessive number of 'AccessDenied' events within a one-hour timeframe originating from a single AWS IAM user. This behavior can indicate an adversary attempting to discover cloud infrastructure and resources by making numerous API calls that they do not have permissions for. The rule specifically looks for more than 5 'AccessDenied' events, involving more than one target application and more than one product event type, from the same user within an hour.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
7058
This rule detects an excessive number of successful AWS API calls related to discovery activities (e.g., Describe*, List*, Get*) originating from a single IAM user within a 5-minute timeframe. This behavior can indicate an adversary attempting to map out the cloud environment after gaining initial access.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
5054
Detects when an existing password policy is updated or deleted in an AWS account. This could indicate an adversary attempting to weaken password requirements to facilitate brute-force attacks or to remove obstacles for credential reuse.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1046
This rule detects when an EC2 instance makes a high number of API calls within a 5-minute window. The rule specifically looks for API calls originating from an assumed role associated with an EC2 instance, identified by a user ID matching the pattern `/i-.*$/`. A high number is defined as more than 7 distinct product event types within the specified timeframe. This behavior can indicate reconnaissance or other malicious activity from a compromised instance.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1044
This rule detects the creation of new applications within Microsoft Entra ID (formerly Azure AD). While application creation is a legitimate administrative activity, it does not occur frequently. Monitoring this event can help identify unauthorized or suspicious application registrations that could be used for persistence, privilege escalation, or other malicious activities within the cloud environment.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1033
This rule detects when a permission on a pre-defined watchlist is applied to an Entra ID application. It specifically looks for 'Update application.' events in Office 365 logs where the 'NewValue_EntitlementId-' or 'OldValue_EntitlementId-' labels indicate a change in application permissions. The rule leverages a watchlist named 'msgraph_watchlist_permissions' to identify sensitive or suspicious permission changes.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
0029
Detects when an excessive number of permissions are assigned to an Entra ID application within a short time window, calculated as a percentage increase from existing permissions. This could indicate a "greedy permission grab" by an attacker attempting to escalate privileges or gain broader access within the Entra ID environment. The rule specifically looks for updates to application permissions where the percentage increase of new permissions over old permissions exceeds a 70% threshold.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1029
Detects excessive PermissionDenied events within an hour timeframe from a user
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
105
Detects instances where an SNMP service on an OpenCanary node has had an OID request.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
001
Detects external IP address lookups by non-browser processes via services such as "api.ipify.org". This could be indicative of potential post compromise internet test activity.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
000
Detects excessive AccessDenied events within an hour timeframe from an IAM User
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
001
Detect when an EC2 instance makes high number of API calls.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
000
Detects excessive successful events within a 5 minute timeframe from an IAM User.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
000
Detects when an existing password policy is updated or deleted in an AWS account.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
000
Detects enumeration of local system accounts on Linux. This information can help adversaries determine which local accounts exist on a system to aid in follow-on behavior. The rule identifies common commands and file accesses used for this purpose, such as 'lastlog', 'id', 'lsof -u', and utilities like 'cat', 'head', 'tail' accessing '/etc/passwd', '/etc/shadow', or '/etc/sudoers'.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
3029
This rule detects the execution of common Linux utilities used for process discovery. Adversaries often use these commands (atop, htop, pgrep, ps, pstree, top) to gather information about running processes on a system, which helps them understand the environment and plan subsequent actions. This information can reveal common software or applications running on systems within the network.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
1020
Detects attempts to query the contents of the event log using command line utilities such as `wevtutil.exe`, `wmic.exe`, and PowerShell cmdlets like `Get-WinEvent` or `Get-EventLog`. Attackers use this technique to find sensitive information in logs, such as credentials, usernames, or IP addresses.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
2068
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