Sigma Rules
241 rules found
Potential Suspicious Change To Sensitive/Critical Files
Detects changes of sensitive and critical files. Monitors files that you don't expect to change without planning on Linux system.
Shell Execution Of Process Located In Tmp Directory
Detects execution of shells from a parent process located in a temporary (/tmp) directory
Execution Of Script Located In Potentially Suspicious Directory
Detects executions of scripts located in potentially suspicious locations such as "/tmp" via a shell such as "bash", "sh", etc.
Mask System Power Settings Via Systemctl
Detects the use of systemctl mask to disable system power management targets such as suspend, hibernate, or hybrid sleep. Adversaries may mask these targets to prevent a system from entering sleep or shutdown states, ensuring their malicious processes remain active and uninterrupted. This behavior can be associated with persistence or defense evasion, as it impairs normal system power operations to maintain long-term access or avoid termination of malicious activity.
System Information Discovery
Detects system information discovery commands
System Network Connections Discovery - Linux
Detects usage of system utilities to discover system network connections
System Network Discovery - Linux
Detects enumeration of local network configuration
Touch Suspicious Service File
Detects usage of the "touch" process in service file.
Triple Cross eBPF Rootkit Execve Hijack
Detects execution of a the file "execve_hijack" which is used by the Triple Cross rootkit as a way to elevate privileges
Triple Cross eBPF Rootkit Install Commands
Detects default install commands of the Triple Cross eBPF rootkit based on the "deployer.sh" script
User Has Been Deleted Via Userdel
Detects execution of the "userdel" binary. Which is used to delete a user account and related files. This is sometimes abused by threat actors in order to cover their tracks
User Added To Root/Sudoers Group Using Usermod
Detects usage of the "usermod" binary to add users add users to the root or suoders groups
Vim GTFOBin Abuse - Linux
Detects the use of "vim" and it's siblings commands to execute a shell or proxy commands. Such behavior may be associated with privilege escalation, unauthorized command execution, or to break out from restricted environments.
Linux Webshell Indicators
Detects suspicious sub processes of web server processes
Download File To Potentially Suspicious Directory Via Wget
Detects the use of wget to download content to a suspicious directory
Potential Xterm Reverse Shell
Detects usage of "xterm" as a potential reverse shell tunnel
SSHD Error Message CVE-2018-15473
Detects exploitation attempt using public exploit code for CVE-2018-15473
Sudo Privilege Escalation CVE-2019-14287 - Builtin
Detects users trying to exploit sudo vulnerability reported in CVE-2019-14287
Sudo Privilege Escalation CVE-2019-14287
Detects users trying to exploit sudo vulnerability reported in CVE-2019-14287
PwnKit Local Privilege Escalation
Detects potential PwnKit exploitation CVE-2021-4034 in auth logs
Atlassian Confluence CVE-2022-26134
Detects spawning of suspicious child processes by Atlassian Confluence server which may indicate successful exploitation of CVE-2022-26134
Potential Nimbuspwn Exploit CVE-2022-29799 and CVE-2022-27800
Detects potential exploitation attempts of Nimbuspwn vulnerabilities CVE-2022-29799 and CVE-2022-27800 in Linux systems.
Apache Spark Shell Command Injection - ProcessCreation
Detects attempts to exploit an apache spark server via CVE-2014-6287 from a commandline perspective
CVE-2023-22518 Exploitation Attempt - Suspicious Confluence Child Process (Linux)
Detects exploitation attempt of CVE-2023-22518 (Confluence Data Center / Confluence Server), where an attacker can exploit vulnerable endpoints to e.g. create admin accounts and execute arbitrary commands.
Potential CVE-2023-2283 Exploitation
Detects potential exploitation attempt of CVE-2023-2283 an authentication bypass in libSSH. The exploitation method causes an error message stating that keys for curve25519 could not be generated. It is an error message that is a sign of an exploitation attempt. It is not a sign of a successful exploitation.
UNC4841 - Email Exfiltration File Pattern
Detects filename pattern of email related data used by UNC4841 for staging and exfiltration
UNC4841 - Barracuda ESG Exploitation Indicators
Detects file indicators as seen used by UNC4841 during their Barracuda ESG zero day exploitation.
UNC4841 - SSL Certificate Exfiltration Via Openssl
Detects the execution of "openssl" to connect to an IP address. This techniques was used by UNC4841 to exfiltrate SSL certificates and as a C2 channel with named pipes. Investigate commands executed in the temporal vicinity of this command.
UNC4841 - Download Compressed Files From Temp.sh Using Wget
Detects execution of "wget" to download a ".zip" or ".rar" files from "temp.sh". As seen used by UNC4841 during their Barracuda ESG zero day exploitation.
UNC4841 - Download Tar File From Untrusted Direct IP Via Wget
Detects execution of "wget" to download a "tar" from an IP address that doesn't have a trusted certificate. As seen used by UNC4841 during their Barracuda ESG zero day exploitation.
UNC4841 - Potential SEASPY Execution
Detects execution of specific named binaries which were used by UNC4841 to deploy their SEASPY backdoor
Potential Exploitation of CVE-2024-3094 - Suspicious SSH Child Process
Detects potentially suspicious child process of SSH process (sshd) with a specific execution user. This could be a sign of potential exploitation of CVE-2024-3094.
Potential SAP NetWeaver Webshell Creation - Linux
Detects the creation of suspicious files (jsp, java, class) in SAP NetWeaver directories, which may indicate exploitation attempts of vulnerabilities such as CVE-2025-31324.
Suspicious Child Process of SAP NetWeaver - Linux
Detects suspicious child processes spawned by SAP NetWeaver on Linux systems that could indicate potential exploitation of vulnerability that allows arbitrary execution via webshells such as CVE-2025-31324.
Non-Standard Nsswitch.Conf Creation - Potential CVE-2025-32463 Exploitation
Detects the creation of nsswitch.conf files in non-standard directories, which may indicate exploitation of CVE-2025-32463. This vulnerability requires an attacker to create a nsswitch.conf in a directory that will be used during sudo chroot operations. When sudo executes, it loads malicious shared libraries from user-controlled locations within the chroot environment, potentially leading to arbitrary code execution and privilege escalation.
Linux Suspicious Child Process from Node.js - React2Shell
Detects suspicious child processes spawned from Node.js server processes on Linux systems, potentially indicating remote code execution exploitation such as CVE-2025-55182 (React2Shell). This rule particularly looks for exploitation of vulnerability on Node.js Servers where attackers abuse Node.js child_process module to execute arbitrary system commands. When execSync() or exec() is used, the command line often includes a shell invocation followed by suspicious commands or scripts (e.g., /bin/sh -c <malicious-command>). For other methods, the Image field will show the spawned process directly.
Shai-Hulud Malicious GitHub Workflow Creation
Detects creation of shai-hulud-workflow.yml file associated with Shai Hulud worm targeting NPM supply chain attack that exfiltrates GitHub secrets
Shai-Hulud Malware Indicators - Linux
Detects potential Shai-Hulud malware indicators based on specific command line arguments associated with its execution.
Shai-Hulud Malicious Bun Execution - Linux
Detects the execution of `bun_environment.js` via the Bun runtime, a behavior associated with the Shai-Hulud "Second Coming" NPM supply chain attack. The malware uses a `setup_bun.js` script to install the Bun runtime if not present, and then executes the malicious `bun_environment.js` payload.
Shai-Hulud 2.0 Malicious NPM Package Installation - Linux
Detects the command-line installation of specific malicious npm packages and versions associated with the Shai-Hulud 2.0 supply chain attack.
Shai-Hulud NPM Package Malicious Exfiltration via Curl
Detects potential Shai Hulud NPM package attack attempting to exfiltrate data via curl to external webhook sites.
Axios NPM Compromise File Creation Indicators - Linux
Detects file creation events linked to the Axios NPM supply chain compromise. Axios is a popular JavaScript HTTP client. On March 30, 2026, malicious versions (1.14.1, 0.30.4) were published to npm, injecting a dependency (plain-crypto-js@4.2.1) that executed a postinstall script as a cross-platform RAT dropper.
Axios NPM Compromise Indicators - Linux
Detects the Linux-specific execution chain of the plain-crypto-js malicious npm dependency by Axios NPM package, including payload download via curl and detached execution using nohup and python3. On March 30, 2026, malicious versions (1.14.1, 0.30.4) were published to npm, injecting a dependency (plain-crypto-js@4.2.1) that executed a postinstall script as a cross-platform RAT dropper. The dropper contacted a C2 server, delivered platform-specific payloads, deleted itself, and replaced package.json to evade detection.
TeamPCP LiteLLM Supply Chain Attack Persistence Indicators
Detects the creation of specific persistence files as observed in the LiteLLM PyPI supply chain attack. In March 2026, a supply chain attack was discovered involving the popular open-source LLM framework LiteLLM by Threat Actor TeamPCP. The malicious package harvests every credential on the system, encrypts and exfiltrates them, and installs a persistent C2 backdoor.
LiteLLM / TeamPCP Supply Chain Attack Indicators
Detects process executions related to the backdoored versions of LiteLLM (v1.82.7 or v1.82.8). In March 2026, a supply chain attack was discovered involving the popular open-source LLM framework LiteLLM by Threat Actor TeamPCP. The malicious package harvests every credential on the system, encrypts and exfiltrates them, and installs a persistent C2 backdoor.
Python Path Configuration File Creation - Linux
Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence. Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script. Default paths are '\lib\site-packages\*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).
Potentially Suspicious Long Filename Pattern - Linux
Detects the creation of files with unusually long filenames (100 or more characters), which may indicate obfuscation techniques used by malware such as VShell. This is a hunting rule to identify potential threats that use long filenames to evade detection. Keep in mind that on a legitimate system, such long filenames can and are common. Run this detection in the context of threat hunting rather than alerting. Adjust the threshold of filename length as needed based on your environment.
Terminate Linux Process Via Kill
Detects usage of command line tools such as "kill", "pkill" or "killall" to terminate or signal a running process.