Detections

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

289 detections

'Identifies contacts with domains names in CommonSecurityLog that might have been generated by a Domain Generation Algorithm (DGA). DGAs can be used by malware to generate rendezvous points that are difficult to predict in advance.
This detection uses the Alexa Top 1 million domain names to build a model of what normal domains look like. It uses this to identify domains that may have been randomly generated by an algorithm.
The triThreshold is set to 500 - increase this to report on domains that are less likely to have been randomly generated, decrease it for more likely.
The start time and end time look back over 6 hours of data and the dgaLengthThreshold is set to 8 - meaning domains whose length is 8 or more are reported.
NOTE - The top1M csv zip file used in the query is dynamic and may produce different results over various time periods. It's important to cross-check the events against the entities involved in the incident.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1072
'This creates an incident in the event a client generates excessive amounts of DNS queries for non-existent domains.
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
2067
'Identifies IP addresses performing DNS lookups associated with common ToR proxies.
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
4065
'Identifies anamalous spikes in network traffic logs as compared to baseline or normal historical patterns.
The query leverages a KQL built-in anomaly detection algorithm to find large deviations from baseline patterns.
Sudden increases in network traffic volume may be an indication of data exfiltration attempts and should be investigated.
The higher the score, the further it is from the baseline value.
The output is aggregated to provide summary view of unique source IP to destination IP address and port traffic observed in the flagged anomaly hour.
The source IP addresses which were sending less than percentotalthreshold of the total traffic have been exluded whose value can be adjusted as needed .
You may have to run queries for individual source IP addresses from SourceIPlist to determine if anything looks suspicious'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0164
The analytic detects outbound SMB (Server Message Block) connections from internal hosts to external servers. It identifies this activity by monitoring network traffic for SMB requests directed towards the Internet, which are unusual for standard operations. This detection is significant for a SOC as it can indicate an attacker's attempt to retrieve credential hashes through compromised servers, a key step in lateral movement and privilege escalation. If confirmed malicious, this activity could lead to unauthorized access to sensitive data and potential full system compromise.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
5082
'This query combines different Storage alerts with CommonSecurityLogs and StorageLogs helping analysts triage and investigate any
possible Storage related attacks faster thus reducing Mean Time To Respond'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
4054
'This query combines different Storage alerts with CommonSecurityLogs and AuditLogs helping analysts investigate any possible storage related attacks faster
thus reducing Mean Time To Respond'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1048
'Identifies a match across various data feeds for domains, hashes and IP IOC related to Mercury
Reference: https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0048
'CreepyDrive uses OneDrive for command and control, however, it makes regular requests to predicatable paths.
This detecton will alert when over 20 sequences are observed in a single day.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1046
'This detection will identify network requests in HTTP proxy data that contains Base64 encoded IP addresses. After identifying candidates the query joins with DeviceNetworkEvents to idnetify any machine within the network using that IP address. Alerts indicate that the IP address of a machine within your network was seen with it's IP address base64 encoded in an outbound web request. This method of egressing the IP was seen used in POLONIUM's RunningRAT tool, however the detection is generic.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1045
The analytic detects instances where network traffic, identified by port and transport layer protocol as prohibited in the "lookup_interesting_ports" table, is allowed. It uses the Network_Traffic data model to cross-reference traffic data against predefined security policies. This activity is significant for a SOC as it highlights potential misconfigurations or policy violations that could lead to unauthorized access or data exfiltration. If confirmed malicious, this could allow attackers to bypass network defenses, leading to potential data breaches and compromising the organization's security posture.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1054
'This detection will alert when RunningRAT URI parameters or paths are detect in an HTTP request.
Id the device blocked this communication presence of this alert means the RunningRAT implant is likely still executing on the source host.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0140
'This detection will identify network requests in HTTP proxy data that contains Base64 encoded usernames from machines in the DeviceEvents table.
This technique was seen usee by POLONIUM in their RunningRAT tool.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0033
'CreepyDrive uses OneDrive for command and control. This detection identifies URLs specific to CreepyDrive.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0023
This analytic detects suspicious modifications to Unix shell configuration files, such as `.bashrc` or `.profile`, which may indicate an attempt to alter system behavior or gain unauthorized access. Unauthorized changes to these files can be used to execute malicious commands, escalate privileges, or hide malicious activities. By monitoring for unusual or unauthorized modifications to shell configuration files, this analytic helps identify potential security threats, allowing security teams to respond quickly and mitigate risks.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
4088
The following analytic detects attempts to stop a service on Linux systems. It leverages data from Linux Auditd. This activity is significant as adversaries often stop or terminate security or critical services to disable defenses or disrupt operations, as seen in malware like Industroyer2. If confirmed malicious, this could lead to the disabling of security mechanisms, allowing attackers to persist, escalate privileges, or deploy destructive payloads, severely impacting system integrity and availability.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0054
The following analytic detects the suspicious auditd service stop. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0051
The analytic detects cloud API calls executed by user roles that have not previously run these commands. It leverages the Change data model in Splunk to identify commands executed by users with the user_type of AssumedRole and a status of success. This activity is significant because new commands from different user roles can indicate potential malicious activity or unauthorized actions. If confirmed malicious, this behavior could lead to unauthorized access, data breaches, or other damaging outcomes by exploiting new or unmonitored commands within the cloud environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1067
The analytic detects the creation of cloud compute instances using previously unseen image IDs. It leverages cloud infrastructure logs to identify new image IDs that have not been observed before. This activity is significant because it may indicate unauthorized or suspicious activity, such as the deployment of malicious payloads or unauthorized access to sensitive information. If confirmed malicious, this could lead to data breaches, unauthorized access, or further compromise of the cloud environment. Immediate investigation is required to determine the legitimacy of the instance creation and to mitigate potential threats.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0067
The following analytic detects the suspicious sysmon service stop. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0036
The following analytic detects the creation of EC2 instances with previously unseen instance types. It leverages Splunk's tstats command to analyze data from the Change data model, identifying instance types that have not been previously recorded. This activity is significant for a SOC because it may indicate unauthorized or suspicious activity, such as an attacker attempting to create instances for malicious purposes. If confirmed malicious, this could lead to unauthorized access, data exfiltration, system compromise, or service disruption. Immediate investigation is required to determine the legitimacy of the instance creation.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0038
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