Detections

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

532 detections

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
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Splunk Security Content
1 year ago
4084
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
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Splunk Security Content
1 year ago
0051
The analytic identifies a significant increase in data transfers from an email server to client hosts. It uses statistical analysis on network traffic to detect anomalies based on average and standard deviation of outbound bytes. This activity is significant as it may indicate a malicious actor exfiltrating data via the email server, potentially leading to unauthorized data access and breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0044
The analytic identifies hosts receiving an unusually high volume of network traffic from an email server. It leverages the Network_Traffic data model to sum incoming bytes to clients from email servers, comparing current traffic against historical averages and standard deviations. This activity is significant as it may indicate data exfiltration by a malicious actor using the email server. If confirmed malicious, this could lead to unauthorized data access and potential data breaches, compromising sensitive information and impacting organizational security.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0042
The analytic identifies the use of SNICat tool commands within the TLS SNI field, indicating potential data exfiltration attempts. It leverages Zeek SSL data to detect specific SNICat commands such as LIST, LS, SIZE, LD, CB, EX, ALIVE, EXIT, WHERE, and finito in the server_name field. This activity is significant as SNICat is a known tool for covert data exfiltration using TLS. If confirmed malicious, this could allow attackers to exfiltrate sensitive data undetected, posing a severe threat to data confidentiality and integrity.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0033
Detects the execution of PowerShell scripts that use the 'Start-NetEventSession' cmdlet to initiate network event and packet capture. This activity can be leveraged by adversaries to sniff network traffic, potentially capturing sensitive information like user credentials, especially when transmitted over unencrypted protocols. This technique is often used for information gathering during an operation.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
0025
Detects command line patterns associated with the use of Pnscan for sending and receiving binary data across the network. This behavior has been identified in a Linux malware campaign targeting Docker, Apache Hadoop, Redis, and Confluence and was previously used by the threat actor known as TeamTNT.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
2023
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