Detections

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

128 detections

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
The following analytic detects `spoolsv.exe` writing a `.dll` file, which is unusual behavior and may indicate exploitation of vulnerabilities like CVE-2021-34527 (PrintNightmare). This detection leverages Sysmon EventID 11 to monitor file creation events in the `\spool\drivers\x64\` directory. This activity is significant because `spoolsv.exe` typically does not write DLL files, and such behavior could signify an ongoing attack. If confirmed malicious, this could allow an attacker to execute arbitrary code, escalate privileges, or maintain persistence on the compromised system.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0055
The following analytic detects a suspicious registry modification aimed at disabling security audit logs by adding a specific registry entry. It leverages data from the Endpoint.Registry data model, focusing on changes to the "Control\\MiniNt" registry path. This activity is significant because it can prevent Windows from logging any events to the Security Log, effectively blinding security monitoring efforts. If confirmed malicious, this technique could allow an attacker to operate undetected, making it difficult to trace their actions and compromising the integrity of security audits.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0054
The following analytic detects the creation of a new DWORD value named "EnableAt" in the registry path "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\Configuration". This modification enables the use of the at.exe or wmi Win32_ScheduledJob commands to add scheduled tasks on a Windows endpoint. The detection leverages registry event data from the Endpoint datamodel. This activity is significant because it may indicate that an attacker is enabling the ability to schedule tasks, potentially to execute malicious code at specific times or intervals. If confirmed malicious, this could allow persistent code execution on the system.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1053
This analytic detects when an unusual number of NTLM authentications is attempted by the same source. This activity generally results when an attacker attempts to brute force, password spray, or otherwise authenticate to a domain joined Windows device using an NTLM based process/attack. This same activity may also generate a large number of EventID 4776 events in as well.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0047
The analytic detects a suspicious registry modification that enables the plain text credential feature in Windows by setting the "UseLogonCredential" value to 1 in the WDigest registry path. This activity is commonly used by malware and tools like Mimikatz to dump plain text credentials, indicating a potential credential dumping attempt. If confirmed malicious, this could allow an attacker to obtain sensitive credentials, leading to further compromise and lateral movement within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1045
The following analytic detects modifications to undocumented registry keys that allow a DLL to load into lsass.exe, potentially capturing credentials. It leverages the Endpoint.Registry data model to identify changes to \CurrentControlSet\Services\NTDS\DirectoryServiceExtPt or \CurrentControlSet\Services\NTDS\LsaDbExtPt. This activity is significant as it indicates a possible attempt to inject malicious code into the Local Security Authority Subsystem Service (LSASS), which can lead to credential theft. If confirmed malicious, this could allow attackers to gain unauthorized access to sensitive information and escalate privileges within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1045
The analytic detects when a device is the target of numerous NTLM authentications using a null domain. This activity generally results when an attacker attempts to brute force, password spray, or otherwise authenticate to a domain joined Windows device from a non-domain device. This activity may also generate a large number of EventID 4776 events in tandem, however these events will not indicate the attacker or target device.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1044
This analytic detects an unusual number of NTLM authentication attempts by a single user account against multiple distinct destinations. This behavior is indicative of an attacker performing brute-force attacks, password spraying, or other NTLM-based authentication attacks to gain access to numerous domain-joined Windows devices. Such activity may also generate a high volume of Event ID 4776 events.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0041
This analytic detects an unusual number of NTLM authentications targeting a single destination using a null domain. This activity is indicative of an attacker attempting to brute force or password spray a domain-joined Windows device from a non-domain device. Such activity may also generate a high volume of EventID 4776 events, though these events might not specify the attacker or target device.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0041
The analytic detects the suspicious loading of DLLs by spoolsv.exe, potentially indicating PrintNightmare exploitation. It leverages Sysmon EventCode 7 to identify instances where spoolsv.exe loads multiple DLLs from the Windows System32 spool drivers x64 directory. This activity is significant as it may signify an attacker exploiting the PrintNightmare vulnerability to execute arbitrary code. If confirmed malicious, this could lead to unauthorized code execution, privilege escalation, and persistent access within the environment, posing a severe security risk.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
1040
The analytic detects when an unusual number of NTLM authentications is attempted by the same source against multiple destinations. This activity generally results when an attacker attempts to brute force, password spray, or otherwise authenticate to multiple domain-joined Windows devices using an NTLM-based process/attack. This same activity may also generate a large number of EventID 4776 events as well.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0040
The following analytic identifies a suspicious modification of the Windows registry setting for max connections per server. It detects changes to specific registry paths using data from the Endpoint.Registry datamodel. This activity is significant because altering this setting can be exploited by attackers to increase the number of concurrent connections to a remote server, potentially facilitating DDoS attacks or enabling more effective lateral movement within a compromised network. If confirmed malicious, this could lead to network disruption or further compromise of additional systems.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0039
This analytic detects the execution of the 'shred' command on a Linux machine, which is used to overwrite files to make them unrecoverable. It leverages data from Linux Auditd, focusing on process names and command-line arguments. This activity is significant because the 'shred' command can be used in destructive attacks, such as those seen in the Industroyer2 malware targeting energy facilities. If confirmed malicious, this activity could lead to the permanent destruction of critical files, severely impacting system integrity and data availability.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0036
The following analytic detects modifications in the Windows registry to disable Windows Error Reporting (WER) settings. It leverages data from the Endpoint.Registry datamodel, specifically monitoring changes to registry paths related to WER with a value set to "0x00000001". This activity is significant as adversaries may disable WER to suppress error notifications, hiding the presence of malicious activities. If confirmed malicious, this could allow attackers to operate undetected, potentially leading to prolonged persistence and further exploitation within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0035
The following analytic detects a modification to the Windows registry setting "LongPathsEnabled," which allows file paths longer than 260 characters. This detection leverages data from the Endpoint.Registry datamodel, focusing on changes to the specific registry path and value. This activity is significant because adversaries, including malware like BlackByte, exploit this setting to bypass file path limitations, potentially aiding in evasion techniques. If confirmed malicious, this modification could facilitate the execution of long-path payloads, aiding in persistence and further system compromise.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0035
The following analytic detects suspicious modifications to the Windows registry keys related to file compression color and information tips. It leverages data from the Endpoint.Registry data model, specifically monitoring changes to the "ShowCompColor" and "ShowInfoTip" values under the "Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced" path. This activity is significant as it was observed in the Hermetic Wiper malware, indicating potential malicious intent to alter file attributes and user interface elements. If confirmed malicious, this could signify an attempt to manipulate file visibility and deceive users, potentially aiding in further malicious activities.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0033
The analytic identifies a source endpoint failing to authenticate with multiple invalid users using the NTLM protocol. It leverages EventCode 4776 and calculates the standard deviation for each host, using the 3-sigma rule to detect anomalies. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges. If confirmed malicious, this activity could lead to unauthorized access or privilege escalation, posing a significant threat to the Active Directory environment. This detection is focused on domain controllers.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0030
The analytic identifies a source endpoint failing to authenticate multiple valid users using the NTLM protocol, potentially indicating a Password Spraying attack. It leverages Event 4776 from Domain Controllers, calculating the standard deviation for each host and applying the 3-sigma rule to detect anomalies. This activity is significant as it may represent an adversary attempting to gain initial access or elevate privileges. If confirmed malicious, the attacker could compromise multiple accounts, leading to unauthorized access and potential lateral movement within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
1 year ago
0028
This rule detects authentication attempts (both successful and failed) originating from a host with a 16-character alphanumeric workstation name, specifically looking for NTLM authentication. This pattern is characteristic of Metasploit's SMB modules, which often generate random 16-character workstation names during authentication attempts. The rule aims to identify potential lateral movement or reconnaissance activities using Metasploit against Windows systems.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
10089
This rule detects NTLM brute force attempts by identifying specific workstation names commonly used by NTLM brute-forcing tools. It looks for Event ID 8004 in the Microsoft-Windows-NTLM/Operational log, specifically when the 'WorkstationName' field matches a list of known tool-related or generic Windows names.
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SigmaHQ Detections@sigmaHQ
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SigmaHQ
2 years ago
1034
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