Detections

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

104 detections

Detects connections held open far longer than normal. Interactive command and
control, tunnelling and remote access tooling all maintain long sessions, whereas
ordinary application traffic is short-lived and bursty.

Duration is available directly in the connection record, which makes this far
cheaper to evaluate than reconstructing sessions from flow data.

Onboarding: NTA is ingested via Network Traffic Analysis (Bloo extractor 717).
Integration guide: https://bloo.io/docs/integrations

BQL (Bloo Query Language):

stream=nta-connection where sourcename='NTA'
and action='CONNECTION_ESTABLISHED'
| duration 24h
| groupby srcip, dstip, dstport, app, duration
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Siddhant Mishra@Siddhant
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Bloo SpecterForce
7 days ago
003
Detects RADIUS authentication activity observed in network traffic, including the
MAC address of the requesting device. Seeing RADIUS on the wire catches
authentication against network infrastructure that often logs nowhere else —
switches, wireless controllers and VPN concentrators.

Onboarding: NTA is ingested via Network Traffic Analysis (Bloo extractor 717).
Integration guide: https://bloo.io/docs/integrations

BQL (Bloo Query Language):

stream=nta-authentication-radius where sourcename='NTA'
| duration 1h
| groupby srcip, dstip, user, macaddress
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Siddhant Mishra@Siddhant
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Bloo SpecterForce
7 days ago
000
Detects a Unix-based (Linux or macOS) browser process spawning a Unix shell that establishes an outbound connection to an external destination.
This browser-to-shell execution chain may indicate malicious browser content, drive-by execution, a compromised website, or abuse of a browser extension on Linux or macOS systems.
The behavior may also occur during legitimate development, installation, automation, or enterprise software workflows.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
1030
This analytic detects the usage of the Utility osascript on a macOS device initiated a network connection lasting longer than 10 minutes (600 seconds).
Adversaries may abuse osascript and AppleScript shell execution to establish long-lived command-and-control or remote connections.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
107
This analytic detects unexpected outbound network connections initiated by known webserver processes such as `httpd.exe`, `nginx.exe`, or `tomcat.exe` to common file sharing or public content hosting services like GitHub, Discord CDN, Transfer.sh, or Pastebin.
Webservers are rarely expected to perform outbound downloads, especially to dynamic or anonymous file hosting domains. This behavior is often associated with server compromise,
where an attacker uses a reverse shell, webshell, or injected task to fetch malware or tools post-exploitation.
The detection leverages Cisco Network Visibility Module flow data, enriched with process context, to identify this highly suspicious behavior.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
303
Detects high-frequency, short-duration UDP flow activity on NetScaler VPN ports (443/4433) indicative of volumetric or malformed DTLS handshake probing, potentially associated with exploitation attempts like CVE-2026-88772.
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Ibrahim Saud@tektrix
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Detections.ai Community
1 month ago
14024
This analytic detects system binaries that are commonly abused in process injection techniques but are observed without any command-line arguments.
It leverages Cisco Network Visibility Module (NVM) flow data and process arguments
to identify outbound connections initiated by curl where TLS checks were explicitly disabled.
Binaries such as `rundll32.exe`, `regsvr32.exe`, `dllhost.exe`, `svchost.exe`, and others are legitimate Windows processes that are often injected into by malware or post-exploitation frameworks (e.g., Cobalt Strike) to hide execution.
When these processes are seen initiating a network connection with an empty or missing command line, it can indicate
potential injection and communication with a command and control server.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
001
This analytic detects the use of `curl.exe` with insecure flags such as `-k`, `--insecure`, `--proxy-insecure`, or `--doh-insecure`
which disable TLS certificate validation.
It leverages Cisco Network Visibility Module (NVM) flow data and process arguments
to identify outbound connections initiated by curl where TLS checks were explicitly disabled.
This behavior may indicate an attempt to bypass certificate validation to connect to potentially untrusted or malicious endpoints,
a common tactic in red team operations, malware staging, or data exfiltration over HTTPS.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
301
This analytic detects suspicious python package installations where the package name resembles popular Python libraries but may be typosquatted or slightly altered.
Typosquatting is a common technique used by attackers to trick users into installing malicious packages that mimic legitimate ones.
This detection leverages Cisco NVM flow telemetry and checks for pip or poetry package managers with the "install" or "add" flags, making outbound connections to package repository such as `pypi.org` with known or suspected typo package names.
Splunk Security@SplunkSecurity
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Splunk Security Content
24 days ago
001
This analytic detects suspicious use of 'mshta.exe' or 'rundll32.exe' invoking 'mshtml.dll'
or the 'RunHTMLApplication' export without including a direct HTTP/HTTPS URL in the command line.
This pattern could be associated with obfuscated script execution used by threat actors during
initial access or payload staging. The absence of a visible URL may indicate attempts to evade static
detections by embedding the URL via string concatenation, encoding (e.g., hex), or indirect script loaders
like 'GetObject()'.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
000
This analytic detects suspicious use of `rundll32.exe` in combination with `mshtml.dll` and the export `RunHTMLApplication`.
This behavior is often observed in malware to execute JavaScript or VBScript in memory, enabling payload staging or
bypassing script execution policies and bypassing the usage of the "mshta.exe" binary.
The detection leverages Cisco Network Visibility Module telemetry which offers network flow activity
along with process information such as command-line arguments
If confirmed malicious, this activity may indicate initial access or payload download.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
000
This analytic identifies the use of Chromium-based browsers (like Microsoft Edge) running in headless mode with the `--dump-dom` argument.
This behavior has been observed in attack campaigns such as DUCKTAIL, where browsers are automated to stealthily download content from the internet using direct URLs or suspicious hosting platforms.
The detection focuses on identifying connections to known file-sharing domains or direct IPs extracted from command-line arguments and cross-checks those against the destination of the flow.
Since it leverages Cisco Network Visibility Module telemetry, the rule triggers only if a network connection is made.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
000
This analytic identifies non-browser processes reaching out to public IP lookup or geolocation services,
such as `ipinfo.io`, `icanhazip.com`, `ip-api.com`, and others.
These domains are commonly used by legitimate tools, but their usage outside of browsers may indicate
network reconnaissance, virtual machine detection, or staging by malware.
This activity is observed in post-exploitation frameworks, stealer malware, and advanced threat actor campaigns.
The detection relies on Cisco Network Visibility Module (NVM) telemetry and excludes known browser
processes to reduce noise.
Splunk Security@SplunkSecurity
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Splunk Security Content
22 days ago
000
This rule detects anomalies in outbound network data transfer by comparing the current daily volume of data sent to external, non-private IP addresses against the historical average for those specific sources. It alerts when the daily volume exceeds 500MB and shows a significant spike (3x or more) compared to historical baseline data or when no historical data is available for a new source connection.
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Min Sakka@AlphaOmega
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Detections.ai Community
1 month ago
409
This analytic identifies instances where an internal host has attempted to communicate with 250 or more destination IP addresses using on of the NMAP top 20 ports. Horizontal port scans from internal hosts can indicate reconnaissance or scanning activities, potentially signaling malicious intent or misconfiguration. By monitoring network traffic logs, this detection helps detect and respond to such behavior promptly, enhancing network security and preventing potential threats.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 month ago
002
This rule detects anomalies in outbound network data transfer by comparing the current daily volume of data sent to external, non-private IP addresses against the historical average for those specific sources. It alerts when the daily volume exceeds 500MB and shows a significant spike (3x or more) compared to historical baseline data or when no historical data is available for a new source connection.
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Min Sakka@AlphaOmega
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Detections.ai Community
1 month ago
009
This rule detects anomalies in outbound network data transfer by comparing the current daily volume of data sent to external, non-private IP addresses against the historical average for those specific sources. It alerts when the daily volume exceeds 500MB and shows a significant spike (3x or more) compared to historical baseline data or when no historical data is available for a new source connection.
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Min Sakka@AlphaOmega
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Detections.ai Community
1 month ago
203
This rule detects various event types (email, identity authentication, network connections, and cloud audit logs) originating from or interacting with the specific IP address range 160.79.104.0/22 to 160.79.111.0/22, which is associated with known malicious activity.
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Arnold Chan@slaz
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Midnight Slayer
2 months ago
005
This rule detects various event types (email, identity authentication, network connections, and cloud audit logs) originating from or interacting with the specific IP address range 160.79.104.0/22 to 160.79.111.0/22, which is associated with known malicious activity.
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Arnold Chan@slaz
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Detections.ai Community
2 months ago
104
This rule detects various event types (email, identity authentication, network connections, and cloud audit logs) originating from or interacting with the specific IP address range 160.79.104.0/22 to 160.79.111.0/22, which is associated with known malicious activity.
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Arnold Chan@slaz
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Hunters
2 months ago
003
This rule detects various event types (email, identity authentication, network connections, and cloud audit logs) originating from or interacting with the specific IP address range 160.79.104.0/22 to 160.79.111.0/22, which is associated with known malicious activity.
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Arnold Chan@slaz
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Detection & Hunting Community
2 months ago
001
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