Linux Auditd Possible Access To Credential Files: endpointEndpointNoneversion:13
The following analytic detects attempts to access or dump the contents of /etc/passwd and /etc/shadow files on Linux systems. It leverages data from Linux Auditd, focusing on processes like 'cat', 'nano', 'vim', and 'vi' accessing these files. This activity is significant as it may indicate credential dumping, a technique used by adversaries to gain persistence or escalate privileges. If confirmed malicious, privileges. If confirmed malicious, attackers could obtain hashed passwords for offline cracking, leading to unauthorized access and potential system compromise.
Linux Auditd Disable Or Modify System Firewall: endpointEndpointNoneversion:12
The following analytic detects the suspicious disable or modify system firewall. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Linux Suspicious Redis Activity: endpointEndpointNoneversion:1
The following analytic detects Redis processes spawning a system shell command. This can indicate exploitation activity of a redis server to gain code execution.
Linux Auditd File And Directory Discovery: endpointEndpointNoneversion:9
The following analytic detects suspicious file and directory discovery activities, which may indicate an attacker's effort to locate sensitive documents and files on a compromised system. This behavior often precedes data exfiltration, as adversaries seek to identify valuable or confidential information for theft. By identifying unusual or unauthorized attempts to browse or enumerate files and directories, this analytic helps security teams detect potential reconnaissance or preparatory actions by an attacker, enabling timely intervention to prevent data breaches or unauthorized access.
Linux Auditd Osquery Service Stop: endpointEndpointNoneversion:10
The following analytic detects suspicious stopping of the `osquery` service, which may indicate an attempt to disable monitoring and evade detection. `Osquery` is a powerful tool used for querying system information and detecting anomalies, and stopping its service can be a sign that an attacker is trying to disrupt security monitoring or hide malicious activities. By monitoring for unusual or unauthorized stops of the `osquery` service, this analytic helps identify potential efforts to bypass security controls, enabling security teams to investigate and respond to possible threats effectively.
Linux Shell History Access Via Command Line Utility: endpointEndpointNoneversion:1
The following analytic detects attempts to read shell history files (bash, zsh, fish, etc.).
A history file is a log file that records all the commands executed in a shell on a Linux or Unix-based operating system.
A malicious actor who gains access to a user's shell history file can potentially obtain sensitive information and use it to compromise the user's system and data.
Linux Auditd Setuid Using Setcap Utility: endpointEndpointNoneversion:10
The following analytic detects the execution of the 'setcap' utility to enable the SUID bit on Linux systems. It leverages Linux Auditd data, focusing on process names and command-line arguments that indicate the use of 'setcap' with specific capabilities. This activity is significant because setting the SUID bit allows a user to temporarily gain root access, posing a substantial security risk. If confirmed malicious, an attacker could escalate privileges, execute arbitrary commands with elevated permissions, and potentially compromise the entire system.
Linux Auditd Sysmon Service Stop: endpointEndpointNoneversion:10
The following analytic detects the suspicious sysmon service stop. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Linux Magic SysRq Key Abuse: endpointEndpointNoneversion:5
Detects potential abuse of the Linux Magic SysRq (System Request) key by adversaries with root or sufficient privileges to manipulate or destabilize a system.
Writing to /proc/sysrq-trigger can crash the system, kill processes, or bypass standard logging.
Monitoring SysRq abuse helps detect stealthy post-exploitation activity.
Correlate with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
Linux Suspicious Privileged Container Execution: endpointEndpointNoneversion:1
The following analytic detects the execution of a Docker container with the privileged flag set, or with the pid namespace set to the host.
This can indicate a container running with elevated permissions and access to the underlying system. Actors can hide containers such as this to enable persistent access.
Linux Binary Executed from Shared Memory Directory: endpointEndpointNoneversion:1
The following analytic identifies the execution of a binary by root from Linux shared memory directories (/dev/shm/ and /run/shm/). Threat actors place executables in these directories to persist on high-uptime servers as system backdoors. Both /dev/shm and /run/shm are tmpfs-backed directories that exist only in virtual memory with no persistent storage, making them attractive for staging fileless or semi-fileless malware while avoiding disk forensics.
Linux Auditd Kernel Module Using Rmmod Utility: endpointEndpointNoneversion:10
The following analytic detects suspicious use of the `rmmod` utility for kernel module removal, which may indicate an attacker attempt to unload critical or security-related kernel modules. The `rmmod` command is used to remove modules from the Linux kernel, and unauthorized use can be a tactic to disable security features, conceal malicious activities, or disrupt system operations. By monitoring for unusual or unauthorized `rmmod` activity, this analytic helps identify potential tampering with kernel modules, enabling security teams to take proactive measures to protect system integrity and security.
Linux Auditd Preload Hijack Library Calls: endpointEndpointNoneversion:13
The following analytic detects the use of the LD_PRELOAD environment variable to hijack or hook library functions on a Linux platform. It leverages data from Linux Auditd, focusing on process execution logs that include command-line details. This activity is significant because adversaries, malware authors, and red teamers commonly use this technique to gain elevated privileges and establish persistence on a compromised machine. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, escalate privileges, and maintain long-term access to the system.
Linux Auditd Stop Services: endpointEndpointNoneversion:9
The following analytic detects attempts to stop a service on Linux systems. It leverages data from Linux Auditd. This activity is significant as adversaries often stop or terminate security or critical services to disable defenses or disrupt operations, as seen in malware like Industroyer2. If confirmed malicious, this could lead to the disabling of security mechanisms, allowing attackers to persist, escalate privileges, or deploy destructive payloads, severely impacting system integrity and availability.
Linux Auditd Data Transfer Size Limits Via Split: endpointEndpointNoneversion:10
The following analytic detects suspicious data transfer activities that involve the use of the `split` syscall, potentially indicating an attempt to evade detection by breaking large files into smaller parts. Attackers may use this technique to bypass size-based security controls, facilitating the covert exfiltration of sensitive data. By monitoring for unusual or unauthorized use of the `split` syscall, this analytic helps identify potential data exfiltration attempts, allowing security teams to intervene and prevent the unauthorized transfer of critical information from the network.
Linux Auditd Data Destruction Command: endpointEndpointNoneversion:10
The following analytic detects the execution of a Unix shell command designed to wipe root directories on a Linux host. It leverages data from Linux Auditd, focusing on the 'rm' command with force recursive deletion and the '--no-preserve-root' option. This activity is significant as it indicates potential data destruction attempts, often associated with malware like Awfulshred. If confirmed malicious, this behavior could lead to severe data loss, system instability, and compromised integrity of the affected Linux host. Immediate investigation and response are crucial to mitigate potential damage.
Linux Auditd Find Credentials From Password Stores: endpointEndpointNoneversion:11
The following analytic detects suspicious attempts to find credentials stored in password stores, indicating a potential attacker's effort to access sensitive login information. Password stores are critical repositories that contain valuable credentials, and unauthorized access to them can lead to significant security breaches. By monitoring for unusual or unauthorized activities related to password store access, this analytic helps identify potential credential theft attempts, allowing security teams to respond promptly and prevent unauthorized access to critical systems and data.
Linux Netcat Outbound Connection: endpointEndpointNoneversion:1
The following analytic detects outbound network connections originating from Netcat or Netcat-like binaries on Linux systems.
Netcat is a versatile networking utility that, while legitimate in some contexts, is frequently abused by attackers to establish reverse shells, exfiltrate data, or create persistent backdoor connections to remote systems.
This activity is significant because outbound connections from these binaries often indicate an active compromise, where an attacker may be maintaining command-and-control communication or tunneling malicious traffic.
If confirmed malicious, this could lead to unauthorized data exfiltration, lateral movement, or persistent remote access to the compromised system.
Linux Auditd Hidden Files And Directories Creation: endpointEndpointNoneversion:11
The following analytic detects suspicious creation of hidden files and directories, which may indicate an attacker's attempt to conceal malicious activities or unauthorized data. Hidden files and directories are often used to evade detection by security tools and administrators, providing a stealthy means for storing malware, logs, or sensitive information. By monitoring for unusual or unauthorized creation of hidden files and directories, this analytic helps identify potential attempts to hide or unauthorized creation of hidden files and directories, this analytic helps identify potential attempts to hide malicious operations, enabling security teams to uncover and address hidden threats effectively.
Linux Auditd Hardware Addition Swapoff: endpointEndpointNoneversion:10
The following analytic detects the execution of the "swapoff" command, which disables the swapping of paging devices on a Linux system. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs. This activity is significant because disabling swap can be a tactic used by malware, such as Awfulshred, to evade detection and hinder forensic analysis. If confirmed malicious, this action could allow an attacker to manipulate system memory management, potentially leading to data corruption, system instability, or evasion of memory-based detection mechanisms.
Linux Auditd Base64 Decode Files: endpointEndpointNoneversion:9
The following analytic detects suspicious Base64 decode operations that may indicate malicious activity, such as data exfiltration or execution of encoded commands. Base64 is commonly used to encode data for safe transmission, but attackers may abuse it to conceal malicious payloads. This detection focuses on identifying unusual or unexpected Base64 decoding processes, particularly when associated with critical files or directories. By monitoring these activities, the analytic helps uncover potential threats, enabling security teams to respond promptly and mitigate risks associated with encoded malware or unauthorized data access.
Linux Auditd System Network Configuration Discovery: endpointEndpointNoneversion:9
The following analytic detects suspicious system network configuration discovery activities, which may indicate an adversary's attempt to gather information about the network environment. Such actions typically involve commands or tools used to identify network interfaces, routing tables, and active connections. Detecting these activities is crucial, as they often precede more targeted attacks like lateral movement or data exfiltration. By identifying unusual or unauthorized network discovery efforts, this analytic helps security teams to swiftly detect and respond to potential reconnaissance operations, mitigating the risk of further compromise.
Linux Auditd File Permission Modification Via Chmod: endpointEndpointNoneversion:15
The following analytic detects suspicious file permission modifications using the `chmod` command, which may indicate an attacker attempting to alter access controls on critical files or directories. Such modifications can be used to grant unauthorized users elevated privileges or to conceal malicious activities by restricting legitimate access. By monitoring for unusual or unauthorized `chmod` usage, this analytic helps identify potential security breaches, allowing security teams to respond promptly to prevent privilege escalation, data tampering, or other unauthorized actions on the system.
Linux Auditd Doas Conf File Creation: endpointEndpointNoneversion:11
The following analytic detects the creation of the doas.conf file on a Linux host.
This file is used by the doas utility to allow standard users to perform tasks as root, similar to sudo.
The detection leverages Linux Auditd data, focusing on the creation of the doas.conf file.
This activity is significant because it can indicate an attempt to gain elevated privileges, potentially by an adversary. If confirmed malicious, this could allow an attacker to execute commands with root commands with root privileges, leading to full system compromise.
Linux Suspicious Child Process of PostgreSQL: endpointEndpointNoneversion:1
The following analytic detects PostgreSQL spawning a shell, interpreter, or network utility as a child process.
When an attacker exploits a remote code execution vulnerability in PostgreSQL (such as via malicious COPY TO/FROM PROGRAM, CVE-2019-9193, or an insecurely configured extension), the database process itself becomes the parent of attacker-controlled commands.
Legitimate PostgreSQL processes do not normally fork shells or download tools, making this a high-fidelity signal for post-exploitation activity.
Linux Auditd Nopasswd Entry In Sudoers File: endpointEndpointNoneversion:12
The following analytic detects the addition of NOPASSWD entries to the /etc/sudoers file on Linux systems. It leverages Linux Auditd data 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.
Linux Auditd Unix Shell Configuration Modification: endpointEndpointNoneversion:11
The following analytic detects suspicious access or modifications to Unix shell configuration files, which may indicate an attempt to alter system behavior or gain unauthorized access.
Unix shell configuration files, such as `.bashrc` or `.profile`, control user environment settings and command execution.
Unauthorized changes to these files can be used to execute malicious commands, escalate privileges, or hide malicious activities.
By monitoring for unusual or unauthorized modifications to shell configuration files, this analytic helps identify potential security threats, allowing security teams to respond quickly and mitigate risks.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
Linux Auditd Auditd Daemon Start: endpointEndpointNoneversion:6
The following analytic detects the (re)initialization of the Linux audit daemon (auditd) by identifying log entries of type DAEMON_START. This event indicates that the audit subsystem has resumed logging after being stopped or has started during system boot. While DAEMON_START may be expected during reboots or legitimate configuration changes, it can also signal attempts to re-enable audit logging after evasion, or restarts with modified or reduced rule sets. Monitoring this event in correlation with DAEMON_END, DAEMON_ABORT, and auditctl activity provides visibility into the continuity and integrity of audit logs. Frequent or unexplained DAEMON_START events should be investigated, especially if they are not accompanied by valid administrative or system activity.
Linux Auditd Auditd Service Stop: endpointEndpointNoneversion:10
The following analytic detects the suspicious auditd service stop. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Linux Auditd Auditd Daemon Shutdown: endpointEndpointNoneversion:6
The following analytic detects the unexpected termination of the Linux Audit daemon (auditd) by monitoring for log entries of type DAEMON_END. This event signifies that the audit logging service has stopped, either due to a legitimate system shutdown, manual administrative action, or potentially malicious tampering. Since auditd is responsible for recording critical security events, its sudden stoppage may indicate an attempt to disable security monitoring or evade detection during an attack. This detection should be correlated with system logs to determine whether the shutdown was part of routine maintenance or an anomaly. If confirmed as malicious, this could lead to a compromised system where security events are no longer being logged, allowing attackers to operate undetected. Therefore, monitoring and alerting on auditd shutdown events is crucial for maintaining the integrity of system security monitoring.
Linux Auditd Auditd Daemon Abort: endpointEndpointNoneversion:6
The following analytic detects the abnormal termination of the Linux audit daemon (auditd) by identifying DAEMON_ABORT events in audit logs. These terminations suggest a serious failure of the auditing subsystem, potentially due to resource exhaustion, corruption, or malicious interference. Unlike a clean shutdown, DAEMON_ABORT implies that audit logging may have been disabled without system administrator intent. Alerts should be generated on detection and correlated with DAEMON_START, DAEMON_END, and system logs to determine root cause. If no DAEMON_START follows soon after, or this pattern repeats, it indicates a high-severity issue that impacts log integrity and should be immediately investigated.
Linux Auditd Find Credentials From Password Managers: endpointEndpointNoneversion:11
The following analytic detects suspicious attempts to find credentials stored in password managers, which may indicate an attacker's effort to retrieve sensitive login information. Password managers are often targeted by adversaries seeking to access stored passwords for further compromise or lateral movement within a network. By monitoring for unusual or unauthorized access to password manager files or processes, this analytic helps identify potential credential theft attempts, enabling security teams to respond quickly to protect critical accounts and prevent further unauthorized access.
Linux Auditd Change File Owner To Root: endpointEndpointNoneversion:11
The following analytic detects the use of the 'chown' command to change a file owner to 'root' on a Linux system. It leverages Linux Auditd telemetry, specifically monitoring command-line executions and process details. 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.
Linux Auditd Find Private Keys: endpointEndpoint2025-02-10version:6
The following analytic has been deprecated. The following analytic detects suspicious attempts to find private keys, which may indicate an attacker's effort to access sensitive cryptographic information. Private keys are crucial for securing encrypted communications and data, and unauthorized access to them can lead to severe security breaches, including data decryption and identity theft. By monitoring for unusual or unauthorized searches for private keys, this analytic helps identify potential threats to cryptographic security, enabling security teams to take swift action to protect the integrity and confidentiality of encrypted information.
Linux Auditd Sudo Or Su Execution: endpointEndpointNoneversion:10
The following analytic detects the execution of the "sudo" or "su" command on a Linux operating system. It leverages data from Linux Auditd, focusing on process names and parent process names. This activity is significant because "sudo" and "su" commands are commonly used by adversaries to elevate privileges, potentially leading to unauthorized access or control over the system. If confirmed malicious, this activity could allow attackers to execute commands with root privileges, leading to severe security breaches, data exfiltration, or further system compromise.
Linux Auditd Setuid Using Chmod Utility: endpointEndpointNoneversion:10
The following analytic detects the execution of the chmod utility to set the SUID or SGID bit on files, which can allow users to temporarily gain root or group-level access. This detection leverages data from Linux Auditd, focusing on process names and command-line arguments related to chmod. This activity is significant as it can indicate an attempt to escalate privileges or maintain persistence on a system. If confirmed malicious, an attacker could gain elevated access, potentially compromising sensitive data or critical system functions.
Linux Auditd Private Keys and Certificate Enumeration: endpointEndpointNoneversion:8
The following analytic detects suspicious attempts to find private keys, which may indicate an attacker's effort to access sensitive cryptographic information. Private keys are crucial for securing encrypted communications and data, and unauthorized access to them can lead to severe security breaches, including data decryption and identity theft. By monitoring for unusual or unauthorized searches for private keys, this analytic helps identify potential threats to cryptographic security, enabling security teams to take swift action to protect the integrity and confidentiality of encrypted information.
Linux Auditd Possible Access To Sudoers File: endpointEndpointNoneversion:14
The following analytic detects potential access or modification of the /etc/sudoers file on a Linux system.
It leverages data from Linux Auditd, focusing on events of type PATH or CWD.
This activity could be significant because the sudoers file controls user permissions for executing commands with elevated privileges.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
If confirmed malicious, an attacker could gain persistence or escalate privileges, compromising the security of the targeted host.
Linux Auditd Service Restarted: endpointEndpointNoneversion:10
The following analytic detects the restarting or re-enabling of services on Linux systems using the `systemctl` or `service` commands. It leverages data from Linux Auditd, focusing on process and command-line execution logs. This activity is significant as adversaries may use it to maintain persistence or execute unauthorized actions. If confirmed malicious, this behavior could lead to repeated execution of malicious payloads, unauthorized access, or data destruction. Security analysts should investigate these events to mitigate risks and prevent further compromise.
Linux Auditd Unload Module Via Modprobe: endpointEndpointNoneversion:10
The following analytic detects suspicious use of the `modprobe` command to unload kernel modules, which may indicate an attempt to disable critical system components or evade detection. The `modprobe` utility manages kernel modules, and unauthorized unloading of modules can disrupt system security features, remove logging capabilities, or conceal malicious activities. By monitoring for unusual or unauthorized `modprobe` operations involving module unloading, this analytic helps identify potential tampering with kernel functionality, enabling security teams to investigate and address possible threats to system integrity.
Linux Auditd Doas Tool Execution: endpointEndpointNoneversion:10
The following analytic detects the execution of the 'doas' tool on a Linux host. This tool allows standard users to perform tasks with root privileges, similar to 'sudo'. The detection leverages data from Linux Auditd, focusing on process names and command-line executions. This activity is significant as 'doas' can be exploited by adversaries to gain elevated privileges on a compromised host. If confirmed malicious, this could lead to unauthorized administrative access, potentially compromising the entire system.
Linux Auditd Install Kernel Module Using Modprobe Utility: endpointEndpointNoneversion:11
The following analytic detects the installation of a Linux kernel module using the modprobe utility. It leverages data from Linux Auditd, focusing on process names and command-line executions. This activity is significant because installing a kernel module can indicate an attempt to deploy a rootkit or other malicious kernel-level code, potentially leading to elevated privileges and bypassing security detections. If confirmed malicious, this could allow an attacker to gain persistent, high-level access to the system, compromising its integrity and security.
Linux Auditd Clipboard Data Copy: endpointEndpointNoneversion:9
The following analytic detects the use of the Linux 'xclip' command to copy data from the clipboard. It leverages Linux Auditd telemetry, focusing on process names and command-line arguments related to clipboard operations. This activity is significant because adversaries can exploit clipboard data to capture sensitive information such as passwords or IP addresses. If confirmed malicious, this technique could lead to unauthorized data exfiltration, compromising sensitive information and potentially aiding further attacks within the environment.
Linux Auditd At Application Execution: endpointEndpointNoneversion:10
The following analytic detects the execution of the "At" application in Linux, which can be used by attackers to create persistence entries on a compromised host. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and parent process names associated with "at" or "atd". This activity is significant because the "At" application can be exploited to maintain unauthorized access or deliver additional malicious payloads. If confirmed malicious, this behavior could lead to data theft, ransomware attacks, or other severe consequences. Immediate investigation is required to determine the legitimacy of the execution and mitigate potential risks.
Linux Possible System Binary Backdoor: endpointEndpointNoneversion:1
The following analytic detects the creation or overwrite of commonly targeted Linux system binaries such as cat, ls, cp, ps, mv, netstat, ss, and lsof.
Adversaries may replace these utilities with backdoored versions to hide malicious activity, harvest credentials, or maintain persistence while appearing to use legitimate system tools.
This technique is associated with rootkit deployment and post-exploitation frameworks such as PANIX.
Linux Auditd Add User Account: endpointEndpointNoneversion:10
The following analytic detects the creation of new user accounts on Linux systems using commands like "useradd" or "adduser." It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant as adversaries often create new user accounts to establish persistence on compromised hosts. If confirmed malicious, this could allow attackers to maintain access, escalate privileges, and further compromise the system, posing a severe security risk.
Linux Auditd Possible Access Or Modification Of Sshd Config File: endpointEndpointNoneversion:11
The following analytic detects access, deletion or modification of the ssh_config file on Linux systems.
It leverages data from Linux Auditd, focusing on events of type PATH with a nametype of ("NORMAL", "CREATE", "DELETE").
This activity could be significant because unauthorized changes to ssh_config can allow threat actors to redirect port connections or use unauthorized keys, potentially compromising the system.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
If confirmed malicious, this could lead to unauthorized access, privilege escalation, or persistent backdoor access, posing a severe security risk.
Linux Auditd Service Started: endpointEndpointNoneversion:11
The following analytic detects the suspicious service started. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Linux Auditd Insert Kernel Module Using Insmod Utility: endpointEndpointNoneversion:11
The following analytic detects the insertion of a Linux kernel module using the insmod utility. It leverages data from Linux Auditd, focusing on process execution logs that include process names and command-line details. This activity is significant as it may indicate the installation of a rootkit or malicious kernel module, potentially allowing an attacker to gain elevated privileges and bypass security detections. If confirmed malicious, this could lead to unauthorized code execution, persistent access, and severe compromise of the affected system.
Linux Auditd Data Transfer Size Limits Via Split Syscall: endpointEndpointNoneversion:9
The following analytic detects suspicious data transfer activities that involve the use of the `split` syscall, potentially indicating an attempt to evade detection by breaking large files into smaller parts. Attackers may use this technique to bypass size-based security controls, facilitating the covert exfiltration of sensitive data. By monitoring for unusual or unauthorized use of the `split` syscall, this analytic helps identify potential data exfiltration attempts, allowing security teams to intervene and prevent the unauthorized transfer of critical information from the network.
Linux Auditd Preload Hijack Via Preload File: endpointEndpointNoneversion:12
The following analytic detects suspicious preload hijacking via the `preload` file, which may indicate an attacker's attempt to intercept or manipulate library loading processes.
The `preload` file can be used to force the loading of specific libraries before others, potentially allowing malicious code to execute or alter application behavior.
By monitoring for unusual or unauthorized modifications to the `preload` file, this analytic helps identify attempts to hijack preload mechanisms, enabling security teams to investigate and address potential threats to system integrity and security.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
Windows Suspicious QEMU Execution: endpointEndpointNoneversion:2
Detects execution of the QEMU binary and an image file with the -nographic flag.
This causes it to run in the background without any display.
This has been observed as a persistence and initial access technique by some threat actors to install a rogue linux virtual machine
Linux Auditd Shred Overwrite Command: endpointEndpointNoneversion:9
The following 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.
Linux Auditd Kernel Module Enumeration: endpointEndpointNoneversion:10
The following analytic identifies the use of the 'kmod' process to list kernel modules on a Linux system. This detection leverages data from Linux Auditd, focusing on process names and command-line executions. While listing kernel modules is not inherently malicious, it can be a precursor to loading unauthorized modules using 'insmod'. If confirmed malicious, this activity could allow an attacker to load kernel modules, potentially leading to privilege escalation, persistence, or other malicious actions within the system.
Linux Auditd Dd File Overwrite: endpointEndpointNoneversion:9
The following analytic detects the use of the 'dd' command to overwrite files on a Linux system. It leverages data from Linux Auditd telemetry, focusing on process execution logs that include command-line details. This activity is significant because adversaries often use the 'dd' command to destroy or irreversibly overwrite files, disrupting system availability and services. If confirmed malicious, this behavior could lead to data destruction, making recovery difficult and potentially causing significant operational disruptions.
Linux Auditd Whoami User Discovery: endpointEndpointNoneversion:9
The following analytic detects the suspicious use of the whoami command, which may indicate an attacker trying to gather information about the current user account on a compromised system. The whoami command is commonly used to verify user privileges and identity, especially during initial stages of an attack to assess the level of access. By monitoring for unusual or unauthorized executions of whoami, this analytic helps in identifying potential reconnaissance activities, enabling security teams to take action before the attacker escalates privileges or conducts further malicious operations.
Linux Auditd Find Ssh Private Keys: endpointEndpointNoneversion:11
The following analytic detects suspicious attempts to find SSH private keys, which may indicate an attacker's effort to compromise secure access to systems. SSH private keys are essential for secure authentication, and unauthorized access to these keys can enable attackers to gain unauthorized access to servers and other critical infrastructure. By monitoring for unusual or unauthorized searches for SSH private keys, this analytic helps identify potential threats to network security, allowing security teams to quickly respond and safeguard against unauthorized access and potential breaches.
Linux Auditd Virtual Disk File And Directory Discovery: endpointEndpointNoneversion:10
The following analytic detects suspicious discovery of virtual disk files and directories, which may indicate an attacker's attempt to locate and access virtualized storage environments. Virtual disks can contain sensitive data or critical system configurations, and unauthorized discovery attempts could signify preparatory actions for data exfiltration or further compromise. By monitoring for unusual or unauthorized searches for virtual disk files and directories, this analytic helps identify potential reconnaissance activities, enabling security teams to respond promptly and safeguard against unauthorized access and data breaches.
Linux Auditd File Permissions Modification Via Chattr: endpointEndpointNoneversion:10
The following analytic detects suspicious file permissions modifications using the chattr command, which may indicate an attacker attempting to manipulate file attributes to evade detection or prevent alteration. The chattr command can be used to make files immutable or restrict deletion, which can be leveraged to protect malicious files or disrupt system operations. By monitoring for unusual or unauthorized chattr usage, this analytic helps identify potential tampering with critical files, enabling security teams to quickly respond to and mitigate threats associated with unauthorized file attribute changes.
Linux Shell Pseudo Device Reverse Shell: endpointEndpointNoneversion:1
The following analytic detects the use of shell's /dev/tcp or /dev/udp pseudo-device feature to establish outbound network connections.
This special file system interface allows opening a network socket and sending or receiving data using simple shell commands.
Attackers commonly abuse this native shell capability to create reverse shells without requiring external tools such as netcat, by redirecting shell I/O over a TCP or UDP connection to an attacker-controlled host and port.
Linux Auditd Edit Cron Table Parameter: endpointEndpointNoneversion:10
The following analytic detects the suspicious editing of cron jobs in Linux using the crontab command-line parameter (-e). It identifies this activity by monitoring command-line executions involving 'crontab' and the edit parameter. This behavior is significant for a SOC as cron job manipulations can indicate unauthorized persistence attempts or scheduled malicious actions. If confirmed malicious, this activity could lead to system compromise, unauthorized access, or broader network compromise.
Linux Auditd Database File And Directory Discovery: endpointEndpointNoneversion:10
The following analytic detects suspicious database file and directory discovery activities, which may signal an attacker attempt to locate and assess critical database assets on a compromised system. This behavior is often a precursor to data theft, unauthorized access, or privilege escalation, as attackers seek to identify valuable information stored in databases. By monitoring for unusual or unauthorized attempts to locate database files and directories, this analytic aids in early detection of potential reconnaissance or data breach efforts, enabling security teams to respond swiftly and mitigate the risk of further compromise.
Linux Auditd Add User Account Type: endpointEndpointNoneversion:12
The following analytic detects the suspicious add user account type. This behavior is critical for a SOC to monitor because it may indicate attempts to gain unauthorized access or maintain control over a system. Such actions could be signs of malicious activity. If confirmed, this could lead to serious consequences, including a compromised system, unauthorized access to sensitive data, or even a wider breach affecting the entire network. Detecting and responding to these signs early is essential to prevent potential security incidents.
Linux Auditd Possible Append Cronjob Entry On Existing Cronjob File: endpointEndpointNoneversion:10
The following analytic detects potential tampering with cronjob files on a Linux system.
It leverages logs from Linux Auditd, focusing on events of type PATH or CWD.
This activity could be significant because adversaries often use it for persistence or privilege escalation.
Correlate this with related EXECVE or PROCTITLE events to identify the process or user responsible for the access or modification.
If confirmed malicious, this could allow attackers to execute unauthorized code automatically, leading to system compromises and unauthorized data access, thereby impacting business operations and data integrity.
