Detections

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

107 detections

Detects network traffic to fallback command and control (C2) domains generated by the 'Children Protection' malicious browser extension. The extension uses a Domain Generation Algorithm (DGA) based on the current date to provide resilient C2 infrastructure.
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Elgonad .@elgonad
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Detections.ai Community
9 months ago
0023
This rule detects network connections from devices to a predefined list of known malicious domains. It identifies attempts by internal systems to communicate with command and control servers, phishing sites, or other infrastructure associated with threat actors.
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Ankit Mehta@Secvyn
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Detections.ai Community
10 months ago
511305
Detects DNS queries to known Dynamic DNS (DDNS) providers. Attackers often leverage DDNS services for command and control (C2) infrastructure to evade IP-based blocklists by frequently changing the IP address associated with a domain.
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nomit vyas@xoxo
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Detections.ai Community
10 months ago
90105
This detection identifies Command and Control (C2) communication associated with the FormBook RAT, specifically targeting connections to a known malicious IP address and dynamic DNS domain on an unusual port. Detecting C2 activity is crucial for identifying active compromises and preventing data exfiltration or further malicious commands.
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Mehulkumar Savajani@Msavajani
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Detections.ai Community
11 months ago
6084
These rules detect indicators associated with a campaign where attackers compromised developer accounts and inserted malicious code into over 35 Google Chrome extensions. The first rule identifies suspicious network connections to known malicious IP addresses and command-and-control (C2) domains. The second rule identifies the presence of known malicious Chrome extension names or their corresponding extension IDs, which could indicate the presence of a hijacked extension.
100daysofyara 2025@100daysyara2025
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100 Days of YARA 2025
1 year ago
1062
This rule detects potential Domain Generation Algorithm (DGA) activity by analyzing network connection logs. It identifies suspicious domains based on their structure (length, character set) and then filters them using a trigram analysis. Domains with non-repeating trigrams and rare trigrams (not found in a baseline of Alexa Top 1M domains) are flagged as DGA candidates. The rule then joins these candidates back to the original network logs to identify actual connections to these suspicious domains.
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Ankit Mehta@Secvyn
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Detections.ai Community
1 year ago
110220
This rule detects network connections to known dynamic DNS (DDNS) subdomains. Adversaries often use dynamic DNS services to maintain persistent command and control (C2) communication channels, as these services allow them to frequently change the IP address associated with a static hostname, making it harder for defenders to block or track their infrastructure. These providers also have established domain reputation, and provide legitimate services making blanket IOC rules impossible. The rule identifies connections to specific DDNS providers such as DuckDNS, No-IP, PublicVM, and others.
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Dylan Evans@decksy
Dexter's Laboratory
1 year ago
143176
Detects network traffic to a list of known domains that are related to TamperedChef - PDF Editor.exe - C2 traffic.
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Emil Stahl@emilstahl
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Detections.ai Community
1 year ago
10121
Detects an executable initiating a network connection to "ngrok" tunneling domains.
Attackers were seen using this "ngrok" in order to store their second stage payloads and malware.
While communication with such domains can be legitimate, often times is a sign of either data exfiltration by malicious actors or additional download.
Yamato Security Hayabusa@YamatoSecurityHayabusa
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Yamato Security Hayabusa Rules
1 year ago
0066
'Identifies contacts with domains names in CommonSecurityLog that might have been generated by a Domain Generation Algorithm (DGA). DGAs can be used by malware to generate rendezvous points that are difficult to predict in advance.
This detection uses the Alexa Top 1 million domain names to build a model of what normal domains look like. It uses this to identify domains that may have been randomly generated by an algorithm.
The triThreshold is set to 500 - increase this to report on domains that are less likely to have been randomly generated, decrease it for more likely.
The start time and end time look back over 6 hours of data and the dgaLengthThreshold is set to 8 - meaning domains whose length is 8 or more are reported.
NOTE - The top1M csv zip file used in the query is dynamic and may produce different results over various time periods. It's important to cross-check the events against the entities involved in the incident.'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1072
'Identifies clients with a high NXDomain count which could be indicative of a DGA (cycling through possible C2 domains where most C2s are not live). Alert is generated when a new IP address is seen (based on not being seen associated with
NXDomain records in prior 10-day baseline period).
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
2057
'This rule identifies communication with hosts that have a domain name that might have been generated by a Domain Generation Algorithm (DGA).
DGAs are used by malware to generate rendezvous points that are difficult to predict in advance. This detection uses the top 1 million domain names to build a model of what normal domains look like nad uses the model to identify domains that may have been randomly generated by an algorithm. You can modify the triThreshold and dgaLengthThreshold query parameters to change Analytic Rule sensitivity. The higher the numbers, the less noisy the rule is.
This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM WebSession schema (ASIM WebSession Schema)'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0050
Looks for a logon domain in the Microsoft Entra ID logs, encoded with the same DGA encoding used in the Nobelium campaign.
See Important steps for customers to protect themselves from recent nation-state cyberattacks for more on the Nobelium campaign (formerly known as Solorigate).
This query is inspired by an Azure Sentinel detection.
References:
https://blogs.microsoft.com/on-the-issues/2020/12/13/customers-protect-nation-state-cyberattacks/
https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Hunting%20Queries/DnsEvents/Solorigate-Encoded-Domain-URL.yaml
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1047
This query looks for the DGA pattern of the domain associated with the Nobelium campaign, in order to find other domains with the same activity pattern.
This query is inspired by an Azure Sentinel detection.
Reference - https://raw.githubusercontent.com/Azure/Azure-Sentinel/master/Hunting%20Queries/DnsEvents/Solorigate-DNS-Pattern.yaml
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
1030
'Detects first connection to an unpopular website (possible malicious payload delivery).'
Azure Sentinel@AzureSentinel
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AzureSentinel
1 year ago
0020
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
The analytic identifies Domain Generation Algorithm (DGA) generated domains using a pre-trained deep learning model. It leverages network resolution data to analyze domain names and detect unusual character sequences indicative of DGA activity. Adversaries often use DGAs to generate numerous domain names for command-and-control servers, making it harder to block malicious traffic. If confirmed malicious, this activity could enable attackers to maintain persistent communication with compromised systems, evade detection, and execute further malicious actions.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1040
This rule detects DNS queries to domains that have been created within the last 30 days. This behavior can be indicative of newly registered malicious domains used for command and control, phishing, or other adversarial activities. The rule correlates DNS query events with WHOIS data to identify the domain creation time.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
0041
This rule detects when Amazon GuardDuty identifies an Amazon EC2 instance or a container querying algorithmically generated domains (DGA). DGA activity is often indicative of malware attempting to establish command and control (C2) communication with its operators. The rule specifically looks for GuardDuty findings with the product event type 'DGADomainRequest' and filters out sample findings.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
0036
This rule detects DNS queries for domains that have a very low rolling maximum prevalence (3 or less over a 10-day period). This can indicate newly registered domains, domains used for command and control, or other suspicious activity that has not yet gained widespread legitimate use. The rule correlates DNS events with derived prevalence data to identify these low-prevalence domains.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
1035
Amazon GuardDuty detects an Amazon EC2 instance or a container querying algorithmically generated domains (DGA).
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
2 years ago
001
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