Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
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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.
Detects network traffic potentially associated with a scraper botnet variant that uses the "Hello-World/1.0" user-agent string and performs GET requests. This activity is indicative of reconnaissance or data scraping.
This analytic detects instances where an internal host attempts to communicate with over 500 ports on a single destination IP address. It includes filtering criteria to exclude applications performing scans over ephemeral port ranges, focusing on potential reconnaissance or scanning activities. Monitoring network traffic logs allows for timely detection and response to such behavior, enhancing network security by identifying and mitigating potential threats promptly.
NetworkSignatureInspected just means the network sensor saw and matched a signature (it inspected the packet) — it doesn’t mean the flow was blocked. That’s the problem.
If your machines are negotiating SMB or NTLM with unknown remote IPs, you’ve got a real risk on your hands: data leakage, credential relay, or worm-style propagation. SMB to the Internet is almost never legitimate; if you don’t recognize the remote IP, treat it as suspicious.
The KQL query includes multiple conditions to detect not only default connections on legacy (139) or modern (445) SMB ports, but also cases where SMB is running over non-standard ports (attempts to evade simple port-based detection). It also extracts the SMB negotiation state so you can spot repeated or incomplete negotiation attempts (useful to detect scanning, failed auths, or relay attempts).
If your machines are negotiating SMB or NTLM with unknown remote IPs, you’ve got a real risk on your hands: data leakage, credential relay, or worm-style propagation. SMB to the Internet is almost never legitimate; if you don’t recognize the remote IP, treat it as suspicious.
The KQL query includes multiple conditions to detect not only default connections on legacy (139) or modern (445) SMB ports, but also cases where SMB is running over non-standard ports (attempts to evade simple port-based detection). It also extracts the SMB negotiation state so you can spot repeated or incomplete negotiation attempts (useful to detect scanning, failed auths, or relay attempts).
This analytic detects intrusion events from known threat activity using Cisco Secure Firewall Intrusion Events. It leverages Cisco Secure Firewall Threat Defense IntrusionEvent logs to identify cases where one or multiple Snort signatures associated with a known threat or threat actor activity have been triggered within a one-hour time window. The detection uses a lookup table (cisco_snort_ids_to_threat_mapping) to map Snort signature IDs to known threat actors and their techniques. When multiple signatures associated with the same threat actor are triggered within the time window, and the count of unique signatures matches or exceeds the expected number of signatures for that threat technique, an alert is generated. This helps identify potential coordinated threat activity in your network environment by correlating related intrusion events that occur in close temporal proximity. Currently, this detection will alert on the following threat actors or malware families as defined in the cisco_snort_ids_to_threat_mapping lookup: ArcaneDoor, Static Tundra, AgentTesla, Amadey, AsyncRAT, Chafer, DCRAT, Lumma Stealer, Nobelium, Quasar, Remcos, Snake, Xworm. To add or update threat actors, update the cisco_snort_ids_to_threat_mapping.csv lookup file with new or modified threat names and associated Snort signature IDs.
This rule detects attempts to exploit CVE-2025-49706 in SharePoint by observing POST requests to a vulnerable aspx path, which could result in code execution or server compromise.
Detects network connections to the 'webhook.site' domain, which is used as an exfiltration endpoint by the 'Shai-Halud' supply chain attack campaign. The risk score is elevated if the specific malicious URL path is observed.
Detects processes potentially related to XillenStealer making outbound network connections or DNS queries for telegram.org. This is indicative of command and control or data exfiltration activity.
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.
The analytic detects long URLs containing multiple SQL commands, indicating a potential SQL injection attack. This detection leverages web traffic data, specifically targeting web server destinations with URLs longer than 1024 characters or HTTP user agents longer than 200 characters. SQL injection is significant as it allows attackers to manipulate a web application's database, potentially leading to unauthorized data access or modification. If confirmed malicious, this activity could result in data breaches, unauthorized access, and complete system compromise. Immediate investigation and validation of alerts are crucial to mitigate these risks.
Detects network traffic potentially associated with a scraper botnet variant that uses the "Hello-World/1.0" user-agent string.
Time to live (TTL) values in DNS responses provide valuable threat-hunting insights, including:
- Fast-flux botnets (rotating IPs with low TTLs).
- Malware C2 detection (extremely low TTLs). ( | where TTLs < 10 )
- DNS tunneling (high TTLs or changing TTLs). ( | where TTLs > 86400 )
- Fake domains mimicking real services (TTL anomalies).
- Evasive infrastructure constantly changing TTL values.
You can use the following KQL Query to search for the mentioned cases.
- Fast-flux botnets (rotating IPs with low TTLs).
- Malware C2 detection (extremely low TTLs). ( | where TTLs < 10 )
- DNS tunneling (high TTLs or changing TTLs). ( | where TTLs > 86400 )
- Fake domains mimicking real services (TTL anomalies).
- Evasive infrastructure constantly changing TTL values.
You can use the following KQL Query to search for the mentioned cases.
This KQL Query is oriented to extract the different bits of TCP Flags which helps to review the different state of the connections and identify possible threats associated.
In addition, it allows to filter by specific TCP Flag to detect specific threats based on every case.
In addition, it allows to filter by specific TCP Flag to detect specific threats based on every case.
This rule detects attempts to download known malicious NPM packages from the public npm registry (registry.npmjs.org) by monitoring network connection logs. It specifically looks for tarball (.tgz) downloads of packages and versions that have been identified as compromised or malicious. The rule extracts the package name and version from the download URL and compares it against a predefined list of malicious packages for high-fidelity detection.
This analytic detects the configuration of TFTP services on Cisco IOS devices that could be used to exfiltrate sensitive configuration files. Threat actors like Static Tundra have been observed configuring TFTP servers to make device configuration files accessible for exfiltration after gaining initial access. The detection specifically looks for commands that expose critical configuration files such as startup-config, running-config, and other sensitive system information through TFTP. This activity is particularly concerning as it may represent an attempt to steal credentials, network topology information, and other sensitive data stored in device configurations.
This analytic identifies non-browser processes reaching out to public IP lookup or geolocation services. These services 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.
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 these processes. 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.
Base64 Website Access
YARA-L
Detects a user accessing multiple websites commonly used for Base64 encoding and decoding within a short time frame. This activity could be a precursor to data exfiltration or an attempt to obfuscate malicious commands.
This analytic detects network connections initiated by binaries that are not typically associated with network communication, such as 'notepad.exe', 'calc.exe' or 'write.exe'. It leverages Cisco Network Visibility Module logs to correlate network flow activity with process context, including command-line arguments, process path, and parent process information. These applications are normally used for locally and do not require outbound network access. When they do initiate such connections, it may indicate process hollowing, code injection, or proxy execution, where adversaries abuse a trusted process to mask malicious activity.
This analytic provides comprehensive monitoring of configuration changes on Cisco devices by analyzing archive logs. Configuration archive logging captures all changes made to a device's configuration, providing a detailed audit trail that can be used to identify suspicious or malicious activities. This detection is particularly valuable for identifying patterns of malicious configuration changes that might indicate an attacker's presence, such as the creation of backdoor accounts, SNMP community string modifications, and TFTP server configurations for data exfiltration. By analyzing these logs, security teams can gain a holistic view of configuration changes across sessions and users, helping to detect sophisticated attack campaigns like those conducted by threat actors such as Static Tundra.
This analytic identifies the use of `msxsl.exe` initiating a network connection to a non-private IP address. Although `msxsl.exe` is a legitimate Microsoft utility used to apply XSLT transformations, adversaries can abuse it to execute arbitrary code or load external resources in an evasive manner. This detection leverages Cisco NVM telemetry to identify potentially malicious use of `msxsl.exe` making network connections that may indicate command and control (C2) or data exfiltration activity.
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