Detections

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

1,598 detections

This rule detects attempts to execute files from external WebDAV shares. It specifically looks for HTTP GET requests where the User-Agent header starts with 'Microsoft-WebDAV-MiniRedir/' and the requested URI ends with common executable or script file extensions. This behavior is often observed in initial access campaigns where adversaries leverage WebDAV to deliver and execute malicious payloads.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
1031
Detects strong indicators of a successful device code phishing attack. This rule correlates email events containing Microsoft device login URLs with subsequent Microsoft Entra ID authentication attempts that result in a specific error code (50199 or 0), indicating the user was prompted to confirm the application. The time window for correlation is set to 16 minutes, accounting for the typical 15-minute expiration of device codes.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
00130
Detects executables launched from external WebDAV shares using the WebDAV Explorer integration, commonly seen in initial access campaigns.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
1 year ago
001
Detects access attempts to a newly created domain via WHOIS enrichment.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
002
Detects strong indicators of a successful device code phishing attack.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
003
This rule detects a significant increase in undeliverable emails for a specific user within a short timeframe. This pattern can indicate that a user's account has been compromised and is being used to send out a large volume of phishing or spam emails, leading to many bounce-back messages. It could also suggest a targeted phishing campaign where the sender's email address is being spoofed, and the legitimate user is receiving the undeliverable notifications.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
0057
The following analytic detects suspicious calendar invites sent via GSuite, potentially indicating compromised accounts or malicious internal activity. It leverages GSuite calendar logs, focusing on events where a high volume of invites (over 100) is sent within a 5-minute window. This behavior is significant as it may involve the distribution of malicious links or attachments, posing a security risk. If confirmed malicious, this activity could lead to widespread phishing attacks, unauthorized access, or malware distribution within the organization.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
20102
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
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
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 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
Detects a spike in undeliverable emails, this can be an early indication of a targeted phishing campaign or a compromised user account.
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Google SecOps@GoogleSecOps
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Google SecOps Detection Rules
1 year ago
002
This analytic identifies when built-in Microsoft 365 security detections for suspicious email behaviors are triggered. These alerts often indicate that an attacker may have compromised a mailbox within the environment, leading to activities such as suspicious email sending patterns, user restrictions from sending email, suspicious email forwarding activity, or email sending limits being exceeded. Monitoring these alerts is crucial for responding to potential account compromises and malicious email activities.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
2047
This analytic detects email attachments with an unusually high number of spaces in their file names, which is a common tactic used by attackers to obfuscate file extensions. It leverages the Email data model to identify attachments where the ratio of spaces to the total file name length exceeds 10%. This behavior is significant as it may indicate an attempt to bypass security filters and deliver malicious payloads. If confirmed malicious, this activity could lead to the execution of harmful code or unauthorized access to sensitive information within the recipient's environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0045
The following analytic identifies when a suspicious email is detected within the Microsoft Office 365 ecosystem through the Advanced Threat Protection engine and delivered to an end user. Attackers may execute several attacks through email, any detections from built-in Office 365 capabilities should be monitored and responded to appropriately. Certain premium Office 365 capabilities such as Safe Attachment and Safe Links further enhance these detection and response functions.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1043
The analytic identifies potential adware activity blocked by Zscaler. It leverages web proxy logs to detect blocked actions associated with adware threats. Key data points such as device owner, user, URL category, destination URL, and IP are analyzed. This activity is significant as adware can degrade system performance, lead to unwanted advertisements, and potentially expose users to further malicious content. If confirmed malicious, it could indicate an attempt to compromise user systems, necessitating further investigation and remediation to prevent potential data breaches or system exploitation.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0043
This analytic identifies when a malicious file is detected within the Microsoft Office 365 ecosystem by the Advanced Threat Protection (ATP) engine. Attackers often stage and execute malicious files from within cloud environments like Office 365. Monitoring detections from built-in Office 365 capabilities, such as those enhanced by Safe Attachments and Safe Links, is crucial for identifying and responding to threats.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0042
The following analytic detects the presence of punycode within x509 certificates using Zeek x509 logs. It identifies punycode in the subject alternative name email and other fields by searching for the "xn--" prefix. This activity is significant as punycode can be used in phishing attacks or to bypass domain filters, posing a security risk. If confirmed malicious, attackers could use these certificates to impersonate legitimate domains, potentially leading to unauthorized access or data breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0042
The following analytic identifies the download of potentially malicious file types, such as .scr, .dll, .bat, and .lnk, within a network. It leverages web proxy logs from Zscaler, focusing on blocked actions and analyzing fields like deviceowner, user, urlcategory, url, dest, and filename. This activity is significant as these file types are often used to spread malware, posing a threat to network security. If confirmed malicious, this activity could lead to malware execution, data compromise, or further network infiltration.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1042
The analytic identifies emails claiming to be sent from a domain similar to one you are monitoring for potential abuse. It leverages email header data, specifically the sender's address, and cross-references it with a lookup table of known domain permutations generated by the "ESCU - DNSTwist Domain Names" search. This activity is significant as it can indicate phishing attempts or brand impersonation, which are common tactics used in social engineering attacks. If confirmed malicious, this could lead to unauthorized access, data theft, or reputational damage.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1039
The following analytic detects suspicious PDF viewer processes spawning browser application child processes. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process and parent process names. This activity is significant as it may indicate a PDF spear-phishing attempt where a malicious URL link is executed, leading to potential payload download. If confirmed malicious, this could allow attackers to execute code, escalate privileges, or persist in the environment by exploiting the user's browser to connect to a malicious site.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0039
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