Detections

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

67 detections

The analytic identifies excessive DNS query failures by counting DNS responses that do not indicate success, triggering when there are more than 50 occurrences. It leverages the Network_Resolution data model, focusing on DNS reply codes that signify errors. This activity is significant because a high number of DNS failures can indicate potential network misconfigurations, DNS poisoning attempts, or malware communication issues. If confirmed malicious, this activity could lead to disrupted network services, hindered communication, or data exfiltration attempts by attackers.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
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
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Splunk Security Content
1 year ago
1051
Detects DNS TXT records containing strings commonly used for command execution, such as 'IEX' (Invoke-Expression), 'Invoke-Expression', and 'cmd.exe'. This technique can be used by adversaries for command and control (C2) or data exfiltration by embedding commands within DNS responses.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
0044
Detects suspicious DNS error messages that indicate a fatal or suspicious error that could be caused by exploiting attempts. Specifically looks for messages related to dropping source port zero packets, denied AXFR requests, and fatal errors causing an exit.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
2021
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