Detections

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

2,686 detections

The analytic identifies ICMP traffic to external IP addresses with total bytes (sum of bytes in and bytes out) greater than 1,000 bytes. It leverages network traffic data to detect large ICMP packets that aren't blocked and are directed toward external networks. This can indicate information smuggling, covert communication, or command-and-control (C2) activities, potentially signaling ICMP tunneling, unauthorized data transfer, or compromised endpoints.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
10102
This analytic detects potentially suspicious large outbound data transfers from internal to external networks using Cisco Secure Firewall Threat Defense logs. It calculates the total volume of data exchanged per connection by summing InitiatorBytes and ResponderBytes. Connections exceeding 100 MB are flagged, as these may indicate unauthorized data exfiltration, especially if initiated by unusual users, hosts, or processes. The detection is scoped to inside-to-outside network flows. If confirmed malicious, this behavior may reflect data staging and exfiltration over an encrypted or stealthy transport.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
4084
The analytic identifies potential DNS exfiltration using the nslookup application. It detects specific command-line parameters such as query type (TXT, A, AAAA) and retry options, which are commonly used by attackers to exfiltrate data. The detection leverages Endpoint Detection and Response (EDR) telemetry, focusing on process execution logs. This activity is significant as it may indicate an attempt to communicate with a Command and Control (C2) server or exfiltrate sensitive data. If confirmed malicious, this could lead to data breaches and unauthorized access to critical information.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1077
This analytic detects API calls to enable S3 bucket replication services. It leverages AWS CloudTrail logs to identify `PutBucketReplication` events, focusing on fields like `bucketName`, `ReplicationConfiguration.Rule.Destination.Bucket`, and user details. This activity is significant as it can indicate unauthorized data replication, potentially leading to data exfiltration. If confirmed malicious, attackers could replicate sensitive data to external accounts, leading to data breaches and compliance violations.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1068
The following analytic identifies potential DNS data exfiltration using a pre-trained deep learning model. It leverages DNS request data from the Network Resolution datamodel and computes features from past events between the same source and domain. The model generates a probability score (pred_is_exfiltration_proba) indicating the likelihood of data exfiltration. This activity is significant as DNS tunneling can be used by attackers to covertly exfiltrate sensitive data. If confirmed malicious, this could lead to unauthorized data access and potential data breaches, compromising the organization's security posture.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
2064
The analytic identifies web activity related to employment searches within a network using Zscaler web proxy logs. It focuses on entries categorized as 'Job/Employment Search' and analyzes data points such as device owner, user, URL category, destination URL, and IP. This detection helps monitor potential insider threats by identifying users who may be seeking new employment, which could indicate a risk of data exfiltration or other insider threats, potentially leading to sensitive information leakage or other security breaches.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0064
The following analytic detects a series of AWS API calls related to EC2 snapshots within a short time window, indicating potential exfiltration via EC2 Snapshot modifications. It leverages AWS CloudTrail logs to identify actions such as creating, describing, and modifying snapshot attributes. This activity is significant as it may indicate an attacker attempting to exfiltrate data by sharing EC2 snapshots externally. If confirmed malicious, the attacker could gain access to sensitive information stored in the snapshots, leading to data breaches and potential compliance violations.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1063
The analytic identifies spikes in blocked outbound network connections originating from within an AWS environment. It uses VPC Flow Logs data from CloudWatch, specifically looking for 'blocked' actions from internal IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to external destinations. A spike is determined by comparing the current number of blocked connections against a calculated baseline (average and standard deviation) over time. This detection is significant as it can indicate potential exfiltration attempts or misconfigurations leading to data leakage. If confirmed malicious, such activity could allow attackers to bypass network defenses, leading to unauthorized data transfer or communication with malicious external entities.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
3062
The following analytic detects when an EC2 snapshot is shared with an external AWS account by analyzing AWS CloudTrail events. This detection method leverages CloudTrail logs to identify modifications in snapshot permissions, specifically when the snapshot is shared outside the originating AWS account. This activity is significant as it may indicate an attempt to exfiltrate sensitive data stored in the snapshot. If confirmed malicious, an attacker could gain unauthorized access to the snapshot's data, potentially leading to data breaches or further exploitation of the compromised information.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1061
The following analytic identifies instances where email forwarding has been enabled on mailboxes within an Office 365 environment. It detects this activity by monitoring the Set-Mailbox operation within the o365_management_activity logs, specifically looking for changes to the ForwardingAddress or ForwardingSmtpAddress parameters. This activity is significant as unauthorized email forwarding can lead to data exfiltration and unauthorized access to sensitive information. If confirmed malicious, attackers could intercept and redirect emails, potentially compromising confidential communications and leading to data breaches.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0059
This analytic detects when an excessive number of files are accessed from Office 365 by the same user over a short period of time. This behavior may indicate an attacker staging data for exfiltration or an insider threat removing organizational data. The rule specifically looks for `fileaccessed` operations in the Office 365 Universal Audit Log, excluding SharePoint app access and common image file extensions. It then calculates the count of unique source file names accessed per user and flags users whose access count significantly exceeds the average (3 standard deviations above the mean) and is greater than 50 files. This can help identify malicious actors abusing "open in app" functionality or Graph API-based access to evade typical file download events.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0056
The analytic detects when emails are accessed in Office 365 Exchange via the Microsoft Graph API using the client ID '00000003-0000-0000-c000-000000000000'. It leverages the 'MailItemsAccessed' operation within the Exchange workload, focusing on OAuth-authenticated applications. This activity is significant as unauthorized access to emails can lead to data breaches and information theft. If confirmed malicious, attackers could exfiltrate sensitive information, compromise user accounts, and further infiltrate the organization's network.
Splunk Security@SplunkSecurity
avatar
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
avatar
Splunk Security Content
1 year ago
0053
The analytic identifies blocked destinations within a network that are deemed privacy risks by Zscaler. It leverages web proxy logs, focusing on entries marked as "Privacy Risk." Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This activity is significant for a SOC as it helps monitor and manage privacy risks, ensuring a secure network environment. If confirmed malicious, this activity could indicate attempts to access or exfiltrate sensitive information, posing a significant threat to data privacy and security.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0053
The following analytic identifies potential AWS S3 exfiltration behavior by correlating multiple risk events related to Collection and Exfiltration techniques. It leverages risk events from AWS sources, focusing on instances where two or more unique analytics and distinct MITRE ATT&CK IDs are triggered for a specific risk object. This activity is significant as it may indicate an ongoing data exfiltration attempt, which is critical for security teams to monitor. If confirmed malicious, this could lead to unauthorized access and theft of sensitive information, compromising the organization's data integrity and confidentiality.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1051
The following analytic identifies high inbound or outbound network I/O anomalies in Kubernetes containers. It leverages process metrics from an OTEL collector and Kubelet Stats Receiver, along with data from Splunk Observability Cloud. A lookup table with average and standard deviation values for network I/O is used to detect anomalies persisting over a 1-hour period. This activity is significant as it may indicate data exfiltration, command and control communication, or unauthorized data transfers. If confirmed malicious, it could lead to data breaches, service outages, financial losses, and reputational damage.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0051
This analytic detects when an excessive number of files are synced from Office 365 by the same user over a short period of time. This behavior may indicate an attacker staging data for exfiltration or an insider threat removing organizational data. The rule specifically looks for `filesyncdownload*` operations with a `UserAgent` containing `*SkyDriveSync*` and filters out cases where the `SiteUrl` matches the user's flat ID, which could be legitimate personal sync activity. A threshold of more than 50 unique source file names downloaded by a single user is used to trigger the alert. Additional attention should be taken with any Azure Guest (#EXT#) accounts.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0051
The analytic detects the execution of 7z, 7za, or 7zr processes with command lines pointing to SMB network shares. This activity may indicate an attempt to archive and exfiltrate sensitive files to a network share, a technique observed in CONTI LEAK tools. If confirmed malicious, this behavior could lead to data exfiltration, compromising sensitive information and potentially aiding further attacks.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0051
This analytic identifies suspicious DNS TXT records using a pre-trained deep learning model. It leverages DNS response data from the Network Resolution data model, categorizing TXT records into known types via regular expressions. Records that do not match known patterns are flagged as suspicious. This activity is significant as DNS TXT records can be used for data exfiltration or command-and-control communication. If confirmed malicious, attackers could use these records to covertly transfer data or receive instructions, posing a severe threat to network security.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1051
The analytic identifies a spike in API activity related to the deletion of S3 buckets in an AWS environment. It uses AWS CloudTrail logs to detect anomalies by comparing current deletion activity against a historical baseline. Unusual spikes in S3 bucket deletions could indicate malicious actions such as data exfiltration or unauthorized data destruction, leading to significant data loss, disruption of services, and potential exposure of sensitive information. Immediate investigation is required to determine the legitimacy of the activity.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
0049
This analytic detects when an excessive number of files are downloaded from Office 365 by the same user over a short period of time. Office 365 may bundle these files together as a ZIP file, however each file will have its own download event. This behavior may indicate an attacker staging data for exfiltration or an insider threat removing organizational data. Additional attention should be taken with any Azure Guest (#EXT#) accounts.
Splunk Security@SplunkSecurity
avatar
Splunk Security Content
1 year ago
1049
Page 121 of 128