Detections

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

7,265 detections

Detects the creation or modification of scheduled cron jobs where the command line argument contains '/tmp/'. This behavior is often indicative of an adversary attempting to establish persistence or execute malicious code from a temporary directory using the cron utility.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1025
Detects the execution of the 'curl' command on Linux systems when it includes options to set a custom user agent. This behavior can be indicative of command and control communication or data exfiltration attempts where an adversary tries to mimic legitimate web traffic or evade detection by changing the default user agent string.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1025
Detects the execution of common Linux utilities used to discover system network connections and logged-in users. Specifically, it looks for 'who', 'w', 'last', 'lsof', and 'netstat' commands. It filters out legitimate calls from '/usr/bin/landscape-sysinfo' when 'who' is used.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1025
Detects the usage of the 'usermod' command to add a user to either the 'root' or 'sudoers' group on a Linux system. This activity can indicate privilege escalation or persistence mechanisms by an attacker.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1025
This rule detects the presence of base64 encoded shebangs (e.g., #!/bin/bash) within command-line arguments. Adversaries often encode commands to evade detection and obfuscate their malicious intent. The rule specifically looks for the base64 representations of common shell shebangs, indicating that a script or command containing these might be decoded and executed.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
3024
Detects the execution of the 'crontab -l' command, which is used to list scheduled cron jobs for the current user. This activity can be part of discovery tactics by adversaries to understand the system's scheduled tasks.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0024
Detects file deletion using "rm", "shred" or "unlink" commands which are used often by adversaries to delete files left behind by the actions of their intrusion activity.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1024
Detects execution of the perl binary with the "-e" flag and common strings related to potential reverse shell activity. This rule looks for specific patterns in the command line arguments that indicate an attempt to establish a reverse shell using Perl's networking capabilities.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
2024
Detects the use of the 'chmod' command to modify file permissions in suspicious directory paths commonly used by malware for persistence or evasion. This rule specifically looks for chmod operations within '/tmp/', '/.Library/', '/etc/', and '/opt/' directories.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
2024
This rule detects the use of the 'find' command on Linux systems with specific permission-related arguments. These arguments are often used by attackers during the discovery phase to locate files with unusual permissions, such as SUID/SGID binaries (-perm -4000, -perm -2000, -perm -u=s, -perm -g=s) which can be exploited for privilege escalation, or world-writable files (-perm 0777, -perm -222, -perm -o w) which could be used for persistence or data modification. It also looks for world-executable files (-perm -o x).
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
2024
Detects suspicious child processes spawned from an interactive bash shell. This rule looks for specific command-line patterns (e.g., base64 encoding, pty.spawn for pseudo-terminal allocation) or specific executables (e.g., whoami, iptables, ncat/netcat) that are uncommon to be direct children of an interactive bash session, indicating potential malicious activity like reverse shells or reconnaissance.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1024
Detects the execution of common shell interpreters (bash, csh, dash, fish, ksh, sh, zsh) where the parent process is located within the '/tmp/' directory. This behavior is often indicative of malware, such as GobRAT, dropping and executing malicious components in temporary locations to evade detection.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
2024
Detects the execution of the 'execve_hijack' component of the Triple Cross eBPF rootkit. This specific file is used by the rootkit to elevate privileges by hijacking the 'execve' system call, often in conjunction with the 'sudo' command.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
2024
This rule detects the execution of specific commands associated with the installation of the Triple Cross eBPF rootkit. It looks for commands executed via 'sudo' that contain specific 'tc' (traffic control) parameters, including 'qdisc' and 'filter', along with a network interface like 'enp0s3'. These command line arguments are characteristic of the 'deployer.sh' script used by the Triple Cross rootkit to establish persistence and hide its presence using eBPF.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0024
This rule detects various suspicious exceptions within Django web applications. These exceptions, such as 'SuspiciousOperation' and its subclasses (e.g., 'DisallowedHost', 'InvalidSessionKey', 'RequestDataTooBig'), as well as 'PermissionDenied', often indicate attempts to exploit vulnerabilities, bypass security controls, or engage in other malicious activities against the web application. Monitoring these exceptions can help identify potential attacks like web parameter tampering, session hijacking attempts, or unauthorized access attempts.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0023
This rule detects the execution of the 'cat' command used to append a zip file to an image file. This technique is commonly used in steganography to hide data within seemingly innocuous files. The rule specifically looks for 'cat' being executed with two arguments: one ending in a common image file extension ('.jpg' or '.png') and another ending in '.zip'. This pattern suggests an attempt to concatenate the contents of a zip file onto an image file.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1023
Detects changes to critical syslog daemon configuration files on Linux hosts. Adversaries may modify these files to disable or reconfigure logging, thereby impairing defenses and hindering the detection of their activities.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1023
Detects the use of the 'steghide' utility to extract hidden files from image files (JPG or PNG). Adversaries may use steganography to conceal data and evade detection.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
1023
Detects attempts to exploit the Shellshock vulnerability (CVE-2014-6271) by looking for specific shellshock expressions in log files. These expressions are commonly used to inject and execute arbitrary commands.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0023
Detects suspicious VSFTPD error messages that indicate a fatal or suspicious error that could be caused by exploiting attempts. These errors often suggest malformed requests or attempts to trigger vulnerabilities in the VSFTPD service.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0023
Detects the creation of a new named pipe using the 'mkfifo' utility on Linux systems. Named pipes can be used for inter-process communication and can sometimes be leveraged by adversaries for various purposes, including data exfiltration, command and control, or as a component of more complex malware.
avatar
SigmaHQ Detections@sigmaHQ
avatar
SigmaHQ
2 years ago
0023
Page 339 of 346