Splunk Security

@SplunkSecurity
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2,497 detections

The analytic detects a Kerberos Ticket Granting Ticket (TGT) request using RC4-HMAC encryption (type 0x17) by leveraging Event 4768. This encryption type is outdated and its presence may indicate an OverPass The Hash attack. Monitoring this activity is crucial as it can signify credential theft, allowing adversaries to authenticate to the Kerberos Distribution Center (KDC) using a stolen NTLM hash. If confirmed malicious, this could enable unauthorized access to systems and resources, potentially leading to lateral movement and further compromise within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
The analytic detects the use of the 'chown' command to change a file owner to 'root' on a Linux system. This activity is significant as it may indicate an attempt to escalate privileges by adversaries, malware, or red teamers. If confirmed malicious, this action could allow an attacker to gain root-level access, leading to full control over the compromised host and potential persistence within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
The following analytic detects the addition of NOPASSWD entries to the /etc/sudoers file on Linux systems. It leverages Endpoint Detection and Response (EDR) telemetry to identify command lines containing "NOPASSWD:". This activity is significant because it allows users to execute commands with elevated privileges without requiring a password, which can be exploited by adversaries to maintain persistent, privileged access. If confirmed malicious, this could lead to unauthorized privilege escalation, persistent access, and potential compromise of sensitive data and system integrity.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
The following analytic detects the use of Mimikatz command line parameters associated with pass-the-ticket attacks. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns related to Kerberos ticket manipulation. This activity is significant because pass-the-ticket attacks allow adversaries to move laterally within an environment using stolen Kerberos tickets, bypassing normal access controls. If confirmed malicious, this could enable attackers to escalate privileges, access sensitive information, and maintain persistence within the network.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
The analytic detects modifications to Windows accessibility binaries such as sethc.exe, utilman.exe, osk.exe, Magnify.exe, Narrator.exe, DisplaySwitch.exe, and AtBroker.exe. It leverages filesystem activity data to identify changes to these specific files. This activity is significant because adversaries can exploit these binaries to gain unauthorized access or execute commands without logging in. If confirmed malicious, this could allow attackers to bypass authentication mechanisms, potentially leading to unauthorized system access and further compromise of the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
1040
The analytic detects the addition of new printer drivers by monitoring Windows PrintService operational logs, specifically EventCode 316. This detection leverages log data to identify messages indicating the addition or update of printer drivers, such as "kernelbase.dll" and "UNIDRV.DLL." This activity is significant as it may indicate exploitation attempts related to vulnerabilities like CVE-2021-34527 (PrintNightmare). If confirmed malicious, attackers could gain code execution or escalate privileges, potentially compromising the affected system. Immediate isolation and investigation of the endpoint are recommended.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
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
2 years ago
1040
The following analytic identifies potential threats related to the theft or forgery of authentication certificates. It detects when five or more analytics from the Windows Certificate Services story trigger within a specified timeframe. This detection leverages aggregated risk scores and event counts from the Risk data model. This activity is significant as it may indicate an ongoing attack aimed at compromising authentication mechanisms. If confirmed malicious, attackers could gain unauthorized access to sensitive systems and data, potentially leading to severe security breaches.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
1040
The following analytic detects a potential UAC bypass using the colorui.dll COM Object. It leverages Sysmon EventCode 7 to identify instances where colorui.dll is loaded by a process other than colorcpl.exe, excluding common system directories. This activity is significant because UAC bypass techniques are often used by malware, such as LockBit ransomware, to gain elevated privileges without user consent. If confirmed malicious, this could allow an attacker to execute code with higher privileges, leading to further system compromise and persistence within the environment.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
This rule detects modifications to the Access Control List (ACL) of the domain root object in Active Directory. Such modifications are significant and can have a high impact on the security of the Active Directory environment. The rule specifically looks for EventCode 5136 (A directory service object was modified) where the ObjectClass is 'domainDNS'. It then parses the old and new ACL values to identify specific changes, including the type of access control entry (ACE), flags, access rights, and the security identifier (SID) of the user or group affected. The rule also attempts to resolve SIDs to user or group names for better readability. Microsoft guidance suggests that all changes at this level should be reviewed.
Splunk Security@SplunkSecurity
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Splunk Security Content
2 years ago
0040
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