This rule identifies a sequence of 100 file extension rename events within a set of common file paths by the same process in a timespan of 1 second. Ransomware is a type of malware that encrypts a victim's files or systems and demands payment (usually in cryptocurrency) in exchange for the decryption key. One important indicator of a ransomware attack is the mass encryption of the file system, after which a new file extension is added to the file.

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Discovery of files created by a remote host on sensitive directories and folders. Remote file creation in these directories could indicate a malicious binary or script trying to compromise the system.

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Monitors for a sequence of network activity on atypical ports, prior to receiving a single packet on such a non-standard port, which potentially indicates signal port knocking activity. Port knocking is a covert method of externally opening ports by sending a sequence of packets to previously closed ports, which adversaries may leverage to discreetly gain access without directly alerting traditional monitoring systems.

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Malicious remote file creation, which can be an indicator of lateral movement activity.

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Identifies process execution followed by a file overwrite of an executable by the same parent process. This may indicate an evasion attempt to execute malicious code in a stealthy way.

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This detection rule detects the creation of a shell through a suspicious parent child relationship. Any reverse shells spawned by the specified utilities that use a forked process to initialize the connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish persistence onto a target system.

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Iodine is a tool for tunneling Internet protocol version 4 (IPV4) traffic over the DNS protocol to circumvent firewalls, network security groups, and network access lists while evading detection.

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This rule detects the execution of a process where the LD_PRELOAD environment variable is set. LD_PRELOAD can be used to inject a shared library into a binary at or prior to execution. A threat actor may do this in order to load a malicious shared library for the purposes of persistence, privilege escalation, and defense evasion. This activity is not common and will potentially indicate malicious or suspicious behavior.

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Identifies an outbound network connection attempt followed by a session id change as the root user by the same process entity. This particular instantiation of a network connection is abnormal and should be investigated as it may indicate a potential reverse shell activity via a privileged process.

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This rule is triggered when indicators from the Threat Intel Filebeat module (v8.x) has a match against local file or network observations. This rule was deprecated. See the Setup section for more information and alternative rules.

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This rule is triggered when indicators from the Threat Intel integrations have a match against local file or network observations. This rule was deprecated. See the Setup section for more information and alternative rules.

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Identifies multiple consecutive login failures targeting a root user account from the same source address and within a short time interval. Adversaries will often brute force login attempts on privileged accounts with a common or known password, in an attempt to gain privileged access to systems.

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Identifies a reverse shell via the abuse of named pipes on Linux with the help of OpenSSL or Netcat. First in, first out (FIFO) files are special files for reading and writing to by Linux processes. For this to work, a named pipe is created and passed to a Linux shell where the use of a network connection tool such as Netcat or OpenSSL has been established. The stdout and stderr are captured in the named pipe from the network connection and passed back to the shell for execution.

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Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access.

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User groups in Google Workspace are created to help manage users permissions and access to various resources and applications. The security label is only applied to a group when users within that group are expected to access sensitive data and/or resources so administrators add this label to easily manage security groups better. Adversaries with administrator access may modify a security group to allow external access from members outside the organization. This detection does not capture all modifications to security groups, but only those that could increase the risk associated with them.

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Enumeration of files and directories using built-in tools. Adversaries may use the information discovered to plan follow-on activity.

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Identifies a suspicious Conhost child process which may be an indication of code injection activity.

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This rule is triggered when indicators from the Threat Intel Filebeat module (v7.x) has a match against local file or network observations.

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Identifies process execution events where the command line value contains a long sequence of whitespace characters or multiple occurrences of contiguous whitespace. Attackers may attempt to evade signature-based detections by padding their malicious command with unnecessary whitespace characters. These observations should be investigated for malicious behavior.

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Identifies the creation or patching of potentially malicious role bindings. Users can use role bindings and cluster role bindings to assign roles to Kubernetes subjects (users, groups, or service accounts).

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A request to a web application server contained no identifying user agent string.

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This rule detects when an internal network client sends DNS traffic directly to the Internet. This is atypical behavior for a managed network and can be indicative of malware, exfiltration, command and control, or simply misconfiguration. This DNS activity also impacts your organization's ability to provide enterprise monitoring and logging of DNS, and it opens your network to a variety of abuses and malicious communications.

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Identifies a suspicious local successful logon event where the Logon Package is Kerberos, the remote address is set to localhost, and the target user SID is the built-in local Administrator account. This may indicate an attempt to leverage a Kerberos relay attack variant that can be used to elevate privilege locally from a domain joined limited user to local System privileges.

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Strace is a useful diagnostic, instructional, and debugging tool. This rule identifies a privileged context execution of strace which can be used to escape restrictive environments by instantiating a shell in order to elevate privileges or move laterally.

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Adversaries may attempt to disable the iptables or firewall service in an attempt to affect how a host is allowed to receive or send network traffic.

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Identifies that a login attempt occurred at a forbidden time.

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Identifies that a login attempt has happened from a forbidden location.

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Identifies that the maximum number of failed login attempts has been reached for a user.

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Identifies that the maximum number login sessions has been reached for a user.

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Identifies processes running in a temporary folder. This is sometimes done by adversaries to hide malware.

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Identifies Linux binary apt/apt-get abuse to breakout out of restricted shells or environments by spawning an interactive system shell. The apt utility allows us to manage installation and removal of softwares on Debian based Linux distributions and the activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary awk abuse to breakout out of restricted shells or environments by spawning an interactive system shell. The awk utility is a text processing language used for data extraction and reporting tools and the activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary busybox abuse to break out from restricted environments by spawning an interactive system shell.The busybox is software utility suite that provides several Unix utilities in a single executable file and the activity of spawing a shell is not a standard use of this binary by a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary c89/c99 abuse to break out from restricted environments by spawning an interactive system shell.The c89/c99 utility is an interface to the standard C compilation system and the activity of spawing a shell is not a standard use of this binary by a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary cpulimit abuse to break out from restricted environments by spawning an interactive system shell. The cpulimit utility is used to restrict the CPU usage of a process in cases of CPU or system load exceeding the defined threshold and the activity of spawning a shell is not a standard use of this binary by a user or system administrator. This can potentially indicate a malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary crash abuse to break out from restricted environments by spawning an interactive system shell. The crash utility helps analyze Linux crash dump data or a live system and the activity of spawning a shell is not a standard use of this binary by a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary env abuse to break out from restricted environments by spawning an interactive system shell. The env utility is a shell command for Unix-like operating systems and is used to print a list of environment variables. The activity of spawning a shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary flock abuse to break out from restricted environments by spawning an interactive system shell. The flock utility allows users to manage advisory file locks in shell scripts or on the command line. The activity of spawning a shell is not a standard use of this binary by a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary expect command abuse to break out from restricted environments by spawning an interactive system shell. The expect utility allows us to automate control of interactive applications such as Telnet, FTP, SSH and others. The activity of spawning shell is not a standard use of this binary for a user or system administrator and could potentially indicate malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary find abuse to break out from restricted environments by spawning an interactive system shell. The find command in Unix is a command line utility for walking a file hierarchy. The activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary gcc abuse to break out from restricted environments by spawning an interactive system shell. The gcc utility is a complier system for various languages and mainly used to compile C and C++ programs. The activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies MySQL server abuse to break out from restricted environments by spawning an interactive system shell. The MySQL server is an open source relational database management system. The activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary SSH abuse to break out from restricted environments by spawning an interactive system shell. The SSH protocol is a network protocol that gives users, particularly system administrators, a secure way to access a computer over a network. The activity of spawning shell is not a standard use of this binary for a user or system administrator. It indicates a potentially malicious actor attempting to improve the capabilities or stability of their access.

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Identifies Linux binary find abuse to break out from restricted environments by spawning an interactive system shell. The vi/vim editor is the standard text editor in Linux distributions, and the activity of spawning a shell is not a standard use of this binary by a user or system administrator. This could potentially indicate a malicious actor attempting to improve the capabilities or stability of their access.

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Detects attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service. For more information refer to CVE-2021-34527 and verify that the impacted system is investigated.

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Detects the creation or modification of a print driver with an unusual file name. This may indicate attempts to exploit privilege escalation vulnerabilities related to the Print Spooler service. For more information refer to CVE-2021-34527 and verify that the impacted system is investigated.

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Identifies the export of an Amazon Relational Database Service (RDS) Aurora database snapshot.

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Identifies mshta.exe making a network connection. This may indicate adversarial activity, as mshta.exe is often leveraged by adversaries to execute malicious scripts and evade detection.

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This rule detects network events that may indicate the use of RDP traffic to the Internet. RDP is commonly used by system administrators to remotely control a system for maintenance or to use shared resources. It should almost never be directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector.

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This rule detects network events that may indicate the use of SSH traffic from the Internet. SSH is commonly used by system administrators to remotely control a system using the command line shell. If it is exposed to the Internet, it should be done with strong security controls as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector.

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This rule detects network events that may indicate the use of SSH traffic from the Internet. SSH is commonly used by system administrators to remotely control a system using the command line shell. If it is exposed to the Internet, it should be done with strong security controls as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector.

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Adversaries may encode/decode data in an attempt to evade detection by host- or network-based security controls.

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This rule detects events that may indicate the use of FTP network connections to the Internet. The File Transfer Protocol (FTP) has been around in its current form since the 1980s. It can be a common and efficient procedure on your network to send and receive files. Because of this, adversaries will also often use this protocol to exfiltrate data from your network or download new tools. Additionally, FTP is a plain-text protocol which, if intercepted, may expose usernames and passwords. FTP activity involving servers subject to regulations or compliance standards may be unauthorized.

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Adversaries may encode/decode data in an attempt to evade detection by host- or network-based security controls.

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This rule detects events that use common ports for Internet Relay Chat (IRC) to the Internet. IRC is a common protocol that can be used for chat and file transfers. This protocol is also a good candidate for remote control of malware and data transfers to and from a network.

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The Linux mknod program is sometimes used in the command payload of a remote command injection (RCI) and other exploits. It is used to export a command shell when the traditional version of netcat is not available to the payload.

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The Tcpdump program ran on a Linux host. Tcpdump is a network monitoring or packet sniffing tool that can be used to capture insecure credentials or data in motion. Sniffing can also be used to discover details of network services as a prelude to lateral movement or defense evasion.

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Nmap was executed on a Linux host. Nmap is a FOSS tool for network scanning and security testing. It can map and discover networks, and identify listening services and operating systems. It is sometimes used to gather information in support of exploitation, execution or lateral movement.

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Identifies loadable kernel module errors, which are often indicative of potential persistence attempts.

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Identifies the creation or execution of a cron job. Adversaries may abuse cron jobs to perform task scheduling for initial or recurring execution of malicious code.

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Identifies a suspicious parent child process relationship with cmd.exe descending from PowerShell.exe.

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This rule detects events that may indicate use of a PPTP VPN connection. Some threat actors use these types of connections to tunnel their traffic while avoiding detection.

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This rule detects events that may describe network events of proxy use to the Internet. It includes popular HTTP proxy ports and SOCKS proxy ports. Typically, environments will use an internal IP address for a proxy server. It can also be used to circumvent network controls and detection mechanisms.

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Enumeration or discovery of the Windows registry using reg.exe. This information can be used to perform follow-on activities.

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This rule detects events that may describe SMTP traffic from internal hosts to a host across the Internet. In an enterprise network, there is typically a dedicated internal host that performs this function. It is also frequently abused by threat actors for command and control, or data exfiltration.

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A Socat process is running on a Linux host. Socat is often used as a persistence mechanism by exporting a reverse shell, or by serving a shell on a listening port. Socat is also sometimes used for lateral movement.

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This rule detects events that may describe database traffic (MS SQL, Oracle, MySQL, and Postgresql) across the Internet. Databases should almost never be directly exposed to the Internet, as they are frequently targeted by threat actors to gain initial access to network resources.

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TCP Port 8000 is commonly used for development environments of web server software. It generally should not be exposed directly to the Internet. If you are running software like this on the Internet, you should consider placing it behind a reverse proxy.

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This rule detects network events that may indicate the use of Tor traffic to the Internet. Tor is a network protocol that sends traffic through a series of encrypted tunnels used to conceal a user's location and usage. Tor may be used by threat actors as an alternate communication pathway to conceal the actor's identity and avoid detection.

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The whoami application was executed on a Linux host. This is often used by tools and persistence mechanisms to test for privileged access.

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Adversaries may attempt to get information about running processes on a system.

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Identifies possibly suspicious activity using trusted Windows developer activity.

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RegSvcs.exe and RegAsm.exe are Windows command line utilities that are used to register .NET Component Object Model (COM) assemblies. Adversaries can use RegSvcs.exe and RegAsm.exe to proxy execution of code through a trusted Windows utility.

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An adversary may add the setgid bit to a file or directory in order to run a file with the privileges of the owning group. An adversary can take advantage of this to either do a shell escape or exploit a vulnerability in an application with the setgid bit to get code running in a different user’s context. Additionally, adversaries can use this mechanism on their own malware to make sure they're able to execute in elevated contexts in the future.

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