Detections

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

3,000 detections

The analytic identifies excessive security scanning activities in AWS by detecting a high number of Describe, List, or Get API calls from a single user. It leverages AWS CloudTrail logs to count distinct event names and flags users with more than 50 such events. This behavior is significant as it may indicate reconnaissance activities by an attacker attempting to map out your AWS environment. If confirmed malicious, this could lead to unauthorized access, data exfiltration, or further exploitation of your cloud infrastructure.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
4054
The following analytic detects the assignment of the 'full_access_as_app' permission to an application registration in Office 365 Exchange Online. This detection leverages Office 365 management activity logs and filters Azure Active Directory workload events to identify when the specific permission, identified by GUID 'dc890d15-9560-4a4c-9b7f-a736ec74ec40', is granted. This activity is significant because it provides extensive control over Office 365 operations, including access to all mailboxes and the ability to send mail as any user. If confirmed malicious, this could lead to unauthorized data access, exfiltration, or account compromise. Immediate investigation is required.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0054
This detection identifies when an Azure Service Principal elevates privileges by adding itself to a new app role assignment. This activity indicates a potential privilege escalation attempt where a service principal grants itself additional permissions, which could lead to unauthorized access or control within the Azure environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0054
The following analytic detects access attempts to privileged Active Directory objects, such as Domain Admins or Enterprise Admins. It leverages Windows Security Event Code 4662 to identify when these sensitive objects are accessed. This activity is significant because such objects should rarely be accessed by normal users or processes, and unauthorized access attempts may indicate attacker enumeration or lateral movement within the domain. If confirmed malicious, this activity could allow attackers to escalate privileges, persist in the environment, or gain control over critical domain resources.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1054
The following analytic identifies when an O365 email account hard deletes an excessive number of emails within a short period (within 1 hour). This behavior may indicate a compromised account where the threat actor is attempting to permanently purge a large amount of items from the mailbox. Threat actors may attempt to remove evidence of their activity by purging items from the compromised mailbox. Some account owner legitimate behaviors can trigger this alert, however these actions may not be aligned with organizational expectations / best practice behaviors.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0053
The following analytic detects when high-privilege roles such as "Exchange Administrator," "SharePoint Administrator," or "Global Administrator" are granted within Office 365. It leverages O365 audit logs to identify events where these roles are assigned to any user or service account. This activity is significant for SOCs as these roles provide extensive permissions, allowing broad access and control over critical resources and data. If confirmed malicious, this could enable attackers to gain significant control over O365 resources, access, modify, or delete critical data, and compromise the overall security and functionality of the O365 environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2053
The analytic identifies instances where a user grants consent to an application requesting mail-related permissions within the Office 365 environment. It leverages O365 audit logs, specifically focusing on events related to application permissions and user consent actions. This activity is significant as it can indicate potential security risks, such as data exfiltration or spear phishing, if malicious applications gain access. If confirmed malicious, this could lead to unauthorized data access, email forwarding, or sending malicious emails from the compromised account. Validating the legitimacy of the application and consent context is crucial to prevent data breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0053
This analytic identifies when the allowed domain settings for O365 SharePoint have been changed. With Azure AD B2B collaboration, users and administrators can invite external users to collaborate with internal users. External guest account invitations may also need access to OneDrive/SharePoint resources. These changes should be monitored by security teams as they could potentially lead to unauthorized access.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0053
The analytic detects the assignment of the 'full_access_as_app' permission to an application within Office 365 Exchange Online. This is identified by the GUID 'dc890d15-9560-4a4c-9b7f-a736ec74ec40' and the ResourceAppId '00000002-0000-0ff1-ce00-000000000000'. The detection leverages the azure_monitor_aad data source, focusing on AuditLogs with the operation name 'Update application'. This activity is significant as it grants broad control over Office 365 operations, including full access to all mailboxes and the ability to send emails as any user. If malicious, this could lead to unauthorized access and data exfiltration.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0052
The analytic detects when a user deletes a repository in GitHub Enterprise. The detection monitors GitHub Enterprise audit logs for repository deletion events, which could indicate unauthorized removal of critical source code and project resources. For a SOC, identifying repository deletions is crucial as it may signal account compromise, insider threats, or malicious attempts to destroy intellectual property and disrupt development operations. The impact could be severe, potentially resulting in permanent loss of source code, documentation, project history, and other critical assets if proper backups are not maintained. Repository deletion could halt development workflows, cause significant business disruption, and require substantial effort to restore from backups if available. Additionally, unauthorized repository removal could be part of a larger attack campaign aimed at destroying or compromising enterprise assets.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0052
The following analytic identifies instances where new IP addresses are added to the trusted IPs list in Office 365, potentially allowing users from these IPs to bypass Multi-Factor Authentication (MFA) during login. It leverages O365 audit logs, specifically focusing on events related to the modification of trusted IP settings. This activity is significant because adding trusted IPs can weaken the security posture by bypassing MFA, which is a critical security control. If confirmed malicious, this could lead to unauthorized access, compromising sensitive information and systems. Immediate investigation is required to validate the legitimacy of the IP addition.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2152
This analytic identifies the assignment of sensitive and privileged Azure Active Directory roles to an Azure AD user. Adversaries and red teams alike may assign these roles to a compromised account to establish Persistence in an Azure AD environment. This detection leverages the O365 Universal Audit Log data source.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1052
The analytic detects port security violations on Cisco switches by leveraging logs from Cisco network devices. It specifically looks for events with mnemonics indicating port security violations. This activity is significant because it indicates an unauthorized device attempting to connect to a secured port, potentially bypassing network access controls. If confirmed malicious, this could allow an attacker to gain unauthorized access to the network, leading to data exfiltration, network disruption, or further lateral movement within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0052
The following analytic detects attempts to disable multi-factor authentication (MFA) for an AWS IAM user. It leverages AWS CloudTrail logs to identify events where MFA devices are deleted or deactivated. This activity is significant because disabling MFA can indicate an adversary attempting to weaken account security, potentially to maintain persistence using a compromised account. If confirmed malicious, this action could allow attackers to retain access to the AWS environment without detection, posing a significant risk to the security and integrity of the cloud infrastructure.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0051
This analytic identifies when a self-hosted runner is created in GitHub Enterprise. The detection monitors GitHub Enterprise audit logs for actions related to creating new self-hosted runners at the organization or enterprise level. This behavior warrants monitoring because self-hosted runners execute workflow jobs on customer-controlled infrastructure, which could be exploited by attackers to execute malicious code, access sensitive data, or pivot to other systems. While self-hosted runners are a legitimate feature, their creation should be carefully controlled as compromised runners pose significant security risks. The impact includes potential remote code execution, data exfiltration, and lateral movement within the environment if a runner is compromised. SOC teams should investigate unexpected runner creation events to verify they are authorized and properly secured, especially if created by unfamiliar users or in unusual contexts.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0051
The following analytic detects when the "risk-based step-up consent" security setting in Microsoft 365 is disabled. It monitors Azure Active Directory logs for the "Update authorization policy" operation, specifically changes to the "AllowUserConsentForRiskyApps" setting. This activity is significant because disabling this feature can expose the organization to OAuth phishing threats, allowing users to grant consent to malicious applications. If confirmed malicious, attackers could gain unauthorized access to user data and sensitive information, leading to data breaches and further compromise within the organization.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0051
The following analytic identifies when an O365 email recipient receives and then deletes emails related to password or banking/payroll changes within a short period. This behavior may indicate a compromised account where the threat actor is attempting to redirect the victims payroll to an attacker controlled bank account.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0051
The following analytic detects modifications to the Access Control List (ACL) of the AdminSDHolder object in a Windows domain, specifically the addition of new rules. It leverages EventCode 5136 from the Security Event Log, focusing on changes to the nTSecurityDescriptor attribute. This activity is significant because the AdminSDHolder object secures privileged group members, and unauthorized changes can allow attackers to establish persistence and escalate privileges. If confirmed malicious, this could enable an attacker to control domain-level permissions, compromising the entire Active Directory environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1051
The following analytic identifies the creation of a new AWS IAM policy version that allows access to all resources. It detects this activity by analyzing AWS CloudTrail logs for the CreatePolicyVersion event with a policy document that grants broad permissions. This behavior is significant because it violates the principle of least privilege, potentially exposing the environment to misuse or abuse. If confirmed malicious, an attacker could gain extensive access to AWS resources, leading to unauthorized actions, data exfiltration, or further compromise of the AWS environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1050
The following analytic detects the deletion of CloudWatch log groups in AWS, identified through `DeleteLogGroup` events in CloudTrail logs. This method leverages Amazon Security Lake logs parsed in the OCSF format. The activity is significant because attackers may delete log groups to evade detection and disrupt logging capabilities, hindering incident response efforts. If confirmed malicious, this action could allow attackers to cover their tracks, making it difficult to trace their activities and potentially leading to undetected data breaches or further malicious actions within the compromised AWS environment.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0050
The following analytic detects when AWS S3 bucket versioning is suspended by a user. It leverages AWS CloudTrail logs to identify `PutBucketVersioning` events with the `VersioningConfiguration.Status` set to `Suspended`. This activity is significant because disabling versioning can prevent recovery of deleted or modified data, which is a common tactic in ransomware attacks. If confirmed malicious, this action could lead to data loss and hinder recovery efforts, severely impacting data integrity and availability.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
2150
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