Detections

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

6,208 detections

A malicious file contacting a known Tor Exit Node.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
000
Alert on known Hash contacting known IP with VT Relationships
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
000
Detects an initiated network connection by a non browser process on the system to "azurewebsites.net". The latter was often used by threat actors as a malware hosting and exfiltration site.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
000
Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains. LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet. Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
0016
Detects outbound network connections initiated by `dialer.exe`, an outdated Microsoft utility. This process is known to be targeted by info-stealers for process injection and used to establish command and control (C2) connections, with Rhadamanthys being a common example. The rule filters out connections to common local and private IP ranges to reduce false positives.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
0014
Detects Deno writing a file from a direct HTTP(s) call and writing to the appdata folder or bringing it's own malicious DLL.
This behavior may indicate an attempt to execute remotely hosted, potentially malicious files through deno.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
000
This rule detects suspicious PowerShell invocations characterized by specific command parameters often used in malicious activities. It looks for combinations of parameters like '-nop', '-w hidden', '-c', and '[Convert]::FromBase64String' for base64 encoded commands; '-w hidden', '-noni', '-nop', '-c', 'iex', and 'New-Object' for obfuscated execution; '-w hidden', '-ep bypass', and '-Enc' for encoded command execution; PowerShell commands interacting with 'reg add' to modify 'Run' keys for persistence; and PowerShell using 'New-Object System.Net.WebClient' with '.Download' for downloading content from the internet, often with 'bypass' and 'hidden' window styles. These patterns are commonly associated with malware, post-exploitation frameworks, and adversary tradecraft.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
0020
Detects a suspicious curl process start the adds a file to a web request
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
001
This analytic identifies internal systems that generate a high volume of intrusion detection events within a 30-minute window, specifically leveraging Cisco Secure Firewall Threat Defense logs. It counts hosts that trigger 15 or more Snort-based signatures. A sudden increase in intrusion alerts from a single host can indicate malicious activity such as malware execution, command-and-control communication, vulnerability scanning, or lateral movement. It may also be caused by misconfigured software. Systems exhibiting this pattern require prompt investigation as repeated Snort rule matches are often early indicators of compromise or active exploitation.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
40132
Detects outbound network connection initiated by Microsoft Dialer.
The Microsoft Dialer, also known as Phone Dialer, is a built-in utility application included in various versions of the Microsoft Windows operating system. Its primary function is to provide users with a graphical interface for managing phone calls via a modem or a phone line connected to the computer.
This is an outdated process in the current conext of it's usage and is a common target for info stealers for process injection, and is used to make C2 connections, common example is "Rhadamanthys"
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
000
Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains.
LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet.
Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
000
Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains.
LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet.
Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
000
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
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Splunk Security Content
1 year ago
10102
This analytic detects the use of known suspicious SSL certificates by comparing the SHA1 fingerprint from Cisco Secure Firewall logs against a blacklist. This is crucial for identifying malware distribution, C2 infrastructure, or phishing campaigns that reuse or self-sign certificates. Detection of such activity may indicate beaconing, malware download, or data exfiltration over TLS/SSL.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
5087
The analytic detects the use of .NET classes in PowerShell to download a URL payload directly into memory, a common fileless malware staging technique. It leverages PowerShell Script Block Logging (EventCode=4104) to identify suspicious PowerShell commands involving `system.net.webclient`, `system.net.webrequest`, and `IO.MemoryStream`. This activity is significant as it indicates potential fileless malware execution, which is harder to detect and can bypass traditional file-based defenses. If confirmed malicious, this technique could allow attackers to execute code in memory, evade detection, and maintain persistence in the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2080
This analytic identifies Snort intrusion signatures that have been triggered by ten or more distinct internal IP addresses within a one-hour window. It leverages Cisco Secure Firewall Threat Defense logs and focuses on the IntrusionEvent event type to detect activity that may indicate broad targeting or mass exploitation attempts. This behavior is often associated with opportunistic scanning, worm propagation, or automated exploitation of known vulnerabilities across multiple systems. If confirmed malicious, this could represent the early phase of a coordinated attack aiming to gain a foothold on several hosts or move laterally across the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
6079
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
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Splunk Security Content
1 year ago
1077
The analytic detects potential reverse shell activity by identifying connections involving ports commonly associated with remote access tools, shell listeners, or tunneling utilities. It leverages Cisco Secure Firewall Threat Defense logs and monitors destination ports against a list of non-standard, high-risk port values often used in post-exploitation scenarios. Adversaries frequently configure tools like netcat, Meterpreter, or other backdoors to listen or connect over uncommon ports such as 4444, 2222, or 51820 to bypass standard monitoring and firewall rules. If confirmed malicious, this activity may represent command and control (C2) tunneling, lateral movement, or unauthorized remote access.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2072
This detection identifies when a new Microsoft Intune device health script has been added, updated, or deleted. Intune device remediation scripts can be used by administrators for remote device management, but this functionality can also be abused for SYSTEM-level code execution and lateral movement to Intune-managed devices.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0066
The following analytic detects the use of Certify or Certipy tools to enumerate Active Directory Certificate Services (AD CS) environments. It leverages Endpoint Detection and Response (EDR) data, focusing on specific command-line arguments associated with these tools. This activity is significant because it indicates potential reconnaissance or exploitation attempts targeting AD CS, which could lead to unauthorized access or privilege escalation. If confirmed malicious, attackers could gain insights into the AD CS infrastructure, potentially compromising sensitive certificates and escalating their privileges within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0064
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
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Splunk Security Content
1 year ago
2064
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