Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
207 detections
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The following 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 the Network_Traffic data model to detect large ICMP packet that aren't blocked and are directed toward external networks. We use All_Traffic.bytes in the detection to capture variations in inbound versus outbound traffic sizes, as significant discrepancies or unusually large ICMP exchanges can indicate information smuggling, covert communication, or command-and-control (C2) activities.
If validated as malicious, this could signal ICMP tunneling, unauthorized data transfer, or compromised endpoints requiring immediate investigation.
It leverages the Network_Traffic data model to detect large ICMP packet that aren't blocked and are directed toward external networks. We use All_Traffic.bytes in the detection to capture variations in inbound versus outbound traffic sizes, as significant discrepancies or unusually large ICMP exchanges can indicate information smuggling, covert communication, or command-and-control (C2) activities.
If validated as malicious, this could signal ICMP tunneling, unauthorized data transfer, or compromised endpoints requiring immediate investigation.
The following analytic detects network traffic associated with known remote access software applications
that are covered by Cisco Secure Firewall Application Detectors, such as AnyDesk, GoToMyPC, LogMeIn, and TeamViewer.
It leverages Cisco Secure Firewall Threat Defense Connection Event.
This activity is significant because adversaries often use remote access tools to maintain unauthorized access to compromised environments.
If confirmed malicious, this activity could allow attackers to control systems remotely, exfiltrate
data, or deploy additional malware, posing a severe threat to the organization's security.
that are covered by Cisco Secure Firewall Application Detectors, such as AnyDesk, GoToMyPC, LogMeIn, and TeamViewer.
It leverages Cisco Secure Firewall Threat Defense Connection Event.
This activity is significant because adversaries often use remote access tools to maintain unauthorized access to compromised environments.
If confirmed malicious, this activity could allow attackers to control systems remotely, exfiltrate
data, or deploy additional malware, posing a severe threat to the organization's security.
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.
Adversaries may abuse osascript and AppleScript shell execution to establish long-lived command-and-control or remote connections.
The following analytic detects file downloads that were classified as malware by Cisco Secure Firewall Threat Defense. It relies on the `SHA_Disposition` field with a value of "Malware" and includes metadata such as file name, file_hash hash, and threat classification. This analytic is critical for surfacing file-based threats that are identified via Cisco's AMP or Threat Grid integrations. If confirmed malicious, this could indicate delivery of malware.
The following analytic detects instances where network traffic, identified by port and transport layer protocol as prohibited in the "lookup_interesting_ports" table, is allowed.
It uses the Network_Traffic data model to cross-reference traffic data against predefined security policies.
This activity is significant for a SOC as it highlights potential misconfigurations or policy violations that could lead to unauthorized access or data exfiltration.
If confirmed malicious, this could allow attackers to bypass network defenses, leading to potential data breaches and compromising the organization's security posture.
It uses the Network_Traffic data model to cross-reference traffic data against predefined security policies.
This activity is significant for a SOC as it highlights potential misconfigurations or policy violations that could lead to unauthorized access or data exfiltration.
If confirmed malicious, this could allow attackers to bypass network defenses, leading to potential data breaches and compromising the organization's security posture.
This rule monitors for Cisco ASA/FTD device logs indicating an unexpected process crash (e.g., 'crashinfo', 'Traceback', 'decode-CF process restart') in conjunction with logs related to WebVPN activity or malformed HTTP requests. This pattern is indicative of potential exploitation attempts against the Cisco WebVPN service, such as those targeting CVE-2026-20349.
Detects potential Cobalt Strike or Sliver command and control (C2) beaconing behavior by analyzing network proxy, firewall, and flow logs for common C2 URI patterns, known malicious JA3/JA3S TLS fingerprints, and consistent periodic communication intervals (low jitter) characteristic of automated beacons.
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.
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 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.
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.
The following analytic detects the use of known suspicious SSL certificates in any observed event where the SSL_CertFingerprint field is present. It leverages Cisco Secure Firewall logs and compares the SSL certificate SHA1 fingerprint against a blacklist of certificates associated with malware distribution, command and control (C2) infrastructure, or phishing campaigns. This activity is significant as adversaries often reuse or self-sign certificates across malicious infrastructure, allowing defenders to track and detect encrypted sessions even when domains or IPs change. If confirmed malicious, this may indicate beaconing, malware download, or data exfiltration over TLS/SSL.
The following analytic detects repeated malware file downloads initiated by the same internal host (src) within a short time window. It leverages Cisco Secure Firewall Threat Defense logs and identifies `FileEvent` events with a `SHA_Disposition` of "Malware" and `FileDirection` set to "Download". If ten or more such events occur from the same host within five minutes, this analytic will trigger. This activity may indicate the host is compromised and repeatedly retrieving malicious content either due to command-and-control, malware staging, or automation. If confirmed malicious, this behavior may represent an infection in progress, persistence mechanism, or a malicious downloader.
Detects repeated SSH authentication failures originating from an external source on port 22, where the username pattern appears to be programmatically generated or enumerated (e.g., username followed by digits). This behavior is characteristic of automated brute-force attempts targeting common SSH services.
The following analytic detects file downloads involving executable, archive, or scripting-related file types that are commonly used in malware delivery.
These file types include formats like PE executables, shell scripts, autorun files, installers, and known testing samples such as EICAR.
This detection leverages Cisco Secure Firewall Threat Defense logs and enriches the results using a filetype lookup to provide context.
If confirmed malicious, these downloads could indicate the initial infection vector, malware staging, or scripting abuse.
These file types include formats like PE executables, shell scripts, autorun files, installers, and known testing samples such as EICAR.
This detection leverages Cisco Secure Firewall Threat Defense logs and enriches the results using a filetype lookup to provide context.
If confirmed malicious, these downloads could indicate the initial infection vector, malware staging, or scripting abuse.
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:
* AgentTesla
* Amadey
* ArcaneDoor
* AsyncRAT
* CastleRAT
* Chafer
* DCRAT
* LokiBot
* Lumma Stealer
* Nobelium
* Quasar
* Remcos
* Snake
* Static Tundra
* 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.
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:
* AgentTesla
* Amadey
* ArcaneDoor
* AsyncRAT
* CastleRAT
* Chafer
* DCRAT
* LokiBot
* Lumma Stealer
* Nobelium
* Quasar
* Remcos
* Snake
* Static Tundra
* 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 potential unauthorized account creation by correlating suspicious administrative activity on network edge devices (VPNs, firewalls) with subsequent local administrator account creation on an internal host within a one-hour window. This behavior is indicative of ransomware affiliates exploiting internet-facing infrastructure to gain initial access and escalate privileges.
Detects HTTP requests directed at edge appliances (FortiOS/FortiProxy, SonicWall, Cisco ASA) that match known CVE-associated URI paths, alongside successful administrative authentication to management or VPN interfaces originating from external source IP addresses. This rule is designed to identify potential initial access via vulnerability exploitation or unauthorized administrative login to critical infrastructure.
Detects attempts to access or execute a file named 'cmd.jar' within the Cisco Firepower Management Center (FMC) or Cisco Security Manager (CSM) environment. This filename is associated with web shell activities used for unauthorized command execution on vulnerable Cisco appliances.
Detects the use of 'COPY TO PROGRAM' syntax within Cisco Email Security Appliance (ESA) logs. This pattern is indicative of potential command injection or OS command execution attempts often associated with exploitation of database-related functionalities, specifically targeting Cisco ESA management or backend interfaces.
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.
Detects the use of 'COPY TO PROGRAM' syntax within Cisco Email Security Appliance (ESA) logs. This pattern is indicative of potential command injection or OS command execution attempts often associated with exploitation of database-related functionalities, specifically targeting Cisco ESA management or backend interfaces.
Detects the use of 'COPY TO PROGRAM' syntax within Cisco Email Security Appliance (ESA) logs. This pattern is indicative of potential command injection or OS command execution attempts often associated with exploitation of database-related functionalities, specifically targeting Cisco ESA management or backend interfaces.
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