Detections

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

6,535 detections

The analytic identifies blocked scam-related activities detected by Zscaler within a network. It leverages web proxy logs to examine actions flagged as scam threats, focusing on data points such as device owner, user, URL category, destination URL, and IP. This detection is significant for SOC as it helps in the early identification and mitigation of scam activities, ensuring network safety. If confirmed malicious, this activity could indicate attempts to deceive users, potentially leading to data theft or financial loss.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0085
This analytic detects potentially suspicious large outbound data transfers from internal to external networks using Cisco Secure Firewall Threat Defense logs. It calculates the total volume of data exchanged per connection by summing InitiatorBytes and ResponderBytes. Connections exceeding 100 MB are flagged, as these may indicate unauthorized data exfiltration, especially if initiated by unusual users, hosts, or processes. The detection is scoped to inside-to-outside network flows. If confirmed malicious, this behavior may reflect data staging and exfiltration over an encrypted or stealthy transport.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
4084
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
This analytic identifies unexpected Active Directory replication traffic originating from non-domain controller sources. It specifically looks for network traffic associated with AD replication protocols (ms-dc-replication, drsr, ad drs). Such traffic should typically only occur between legitimate domain controllers. Detection of this activity from other sources may indicate malicious activities like DCSync or DCShadow, which are commonly used for credential dumping and could lead to unauthorized access and potential domain-wide compromise.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
3073
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
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
The analytic identifies web activity related to employment searches within a network using Zscaler web proxy logs. It focuses on entries categorized as 'Job/Employment Search' and analyzes data points such as device owner, user, URL category, destination URL, and IP. This detection helps monitor potential insider threats by identifying users who may be seeking new employment, which could indicate a risk of data exfiltration or other insider threats, potentially leading to sensitive information leakage or other security breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0064
This analytic detects the presence of SIGRed (CVE-2020-1350), a critical DNS vulnerability, using Zeek DNS and Zeek Conn data. It identifies specific DNS query types (SIG and KEY) and checks for high data transfer within a flow (over 65KB). This detection is significant because SIGRed allows attackers to execute remote code on Windows DNS servers, potentially leading to unauthorized access and control. If confirmed malicious, this activity could result in data exfiltration, service disruption, or further network compromise. Immediate investigation and mitigation, such as patching or isolating the affected server, are crucial.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0063
This analytic detects internal hosts triggering multiple IDS signatures, which may include either more than 25 signatures against a single host or a single signature across over 25 destination IP addresses. Such patterns can indicate active vulnerability scanning activities within the network. By monitoring IDS logs, this detection helps identify and respond to potential vulnerability scanning attempts, enhancing the network's security posture and preventing potential exploits.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
4058
This analytic detects file transfers flagged as malware that occurred over non-standard ports (other than 80 and 443) from Cisco Secure Firewall Threat Defense logs. Adversaries may attempt to bypass protocol-based detection or use alternate ports to blend in with other traffic. This analytic identifies these non-conventional flows and surfaces potential evasion techniques. If confirmed malicious, this indicates potential malware delivery or other nefarious activity.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2057
This analytic detects network connections flagged by Cisco Secure Firewall's Encrypted Visibility Engine (EVE) with a high threat confidence score (80% or greater). This indicates that the encrypted traffic is highly likely to be malicious, potentially associated with malware command and control (C2), remote access tools, or suspicious tunneling behavior. Such activity could signify covert communication from compromised hosts.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1055
The analytic identifies excessive DNS query failures by counting DNS responses that do not indicate success, triggering when there are more than 50 occurrences. It leverages the Network_Resolution data model, focusing on DNS reply codes that signify errors. This activity is significant because a high number of DNS failures can indicate potential network misconfigurations, DNS poisoning attempts, or malware communication issues. If confirmed malicious, this activity could lead to disrupted network services, hindered communication, or data exfiltration attempts by attackers.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
This analytic identifies remote code execution (RCE) attempts targeting F5 BIG-IP, BIG-IQ, and Traffix SDC devices, specifically exploiting CVE-2020-5902. It uses regex to detect patterns in syslog data that match known exploit strings such as "hsqldb;" and directory traversal sequences. This activity is significant because successful exploitation can allow attackers to execute arbitrary commands on the affected devices, leading to full system compromise. If confirmed malicious, this could result in unauthorized access, data exfiltration, or further lateral movement within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
The following analytic detects attempts to exploit CVE-2022-40684, a Fortinet appliance authentication bypass vulnerability. It identifies REST API requests to the /api/v2/ endpoint using various HTTP methods (GET, POST, PUT, DELETE) that may indicate unauthorized modifications, such as adding SSH keys or creating new users. This detection leverages the Web datamodel to monitor specific URL patterns and HTTP methods. This activity is significant as it can lead to unauthorized access and control over the appliance. If confirmed malicious, attackers could gain persistent access, reroute network traffic, or capture sensitive information.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
This detection identifies potential exploitation of CVE-2025-24813 in Apache Tomcat through the second stage of the attack. This phase occurs when an attacker attempts to trigger deserialization of a previously uploaded malicious session file by sending a GET request with a specially crafted JSESSIONID cookie. These requests typically have specific characteristics, including a JSESSIONID cookie with a leading dot that matches a previously uploaded filename, and typically result in a HTTP 500 error when the exploitation succeeds.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
The analytic identifies blocked destinations within a network that are deemed privacy risks by Zscaler. It leverages web proxy logs, focusing on entries marked as "Privacy Risk." Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This activity is significant for a SOC as it helps monitor and manage privacy risks, ensuring a secure network environment. If confirmed malicious, this activity could indicate attempts to access or exfiltrate sensitive information, posing a significant threat to data privacy and security.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0053
The analytic detects port security violations on Cisco switches by leveraging logs from Cisco network devices. It specifically looks for events with mnemonics indicating port security violations. This activity is significant because it indicates an unauthorized device attempting to connect to a secured port, potentially bypassing network access controls. If confirmed malicious, this could allow an attacker to gain unauthorized access to the network, leading to data exfiltration, network disruption, or further lateral movement within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0052
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
This analytic detects SSL certificates with Punycode domains in the SSL issuer email domain, identified by the prefix "xn--". It leverages the Certificates Datamodel to flag these domains and uses CyberChef for decoding. This activity is significant as Punycode can be used for domain spoofing and phishing attacks. If confirmed malicious, attackers could deceive users and systems, potentially leading to unauthorized access and data breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0050
The following analytic detects attempts to exploit the CVE-2023-46747 vulnerability, an authentication bypass flaw in F5 BIG-IP's Configuration utility (TMUI). It identifies this activity by monitoring for specific URI paths such as "*/mgmt/tm/auth/user/*" with the PATCH method and a 200 status code. This behavior is significant for a SOC as it indicates potential unauthorized access attempts, leading to remote code execution. If confirmed malicious, an attacker could gain unauthorized access, execute arbitrary code, steal data, disrupt systems, or conduct further malicious activities within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1049
The analytic identifies potential malware activities within a network that are blocked by Zscaler. It leverages web proxy logs to filter for blocked actions associated with malware, aggregating occurrences by user, URL, and threat category. This detection is significant for SOC as it highlights attempts to access malicious content, indicating potential compromise or targeted attacks. If confirmed malicious, this activity could signify an ongoing attempt to infiltrate the network, necessitating immediate investigation to prevent further threats and ensure network integrity.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1049
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