>ruby
Ruby is an interpreted programming language. Attackers use ruby -e one-liners to execute shell breakouts, spawn interactive PTY shells, or establish network socket connections.
Default Executable Paths
/usr/bin/rubyIntegrity & Metadata
Like Perl and Python, Ruby is frequently present on DevOps environments and servers.
Look for ruby processes executing inline "-e" switches invoking exec or spawn functions.
Executive Summary & AI Quick Reference
ruby is a native utility pre-installed on Linux systems. Threat actors and red teams abuse ruby as a Living-off-the-Land Binary (LOLBin) to achieve Execute without triggering traditional antivirus file-hash alerts. Legitimate system administrators use it for routine administration, making behavioral command-line telemetry essential for differentiation.
Weaponized Parameters & Proof-of-Concepts
Documented attack commands, parameter flags, and privilege prerequisites.
Spawns an interactive shell interpreter using Ruby process execution.
ruby -e 'exec "/bin/sh"'SIEM & EDR Detection Rules
Production telemetry rules configured for Microsoft Defender, Sigma, and Splunk.
Telemetry & SIEM Detection Suite (ruby)
Validated against MITRE T10591DeviceProcessEvents | where FileName =~ "ruby" | where ProcessCommandLine has_all ("-e", "exec", "/bin/sh") | project Timestamp, DeviceName, AccountName, ProcessCommandLineMitigation, Hardening & Prevention
Recommended defensive controls to block or constrain ruby abuse.
Audit and remove unnecessary SUID / SGID bits (`chmod u-s /path/to/$ruby`) and restrict sudoers NOPASSWD execution grants.
Implement AppArmor or SELinux profiles restricting ruby network socket creation and read access to sensitive user directories.
Deploy the KQL, Sigma, and Splunk detection queries below. Alert on anomalous child processes, web requests to unrated external IPs, or encoded payload strings.
Frequently Asked Questions (FAQ) • ruby
Key operational questions and defensive answers about ruby LOLBin tradecraft.
What is ruby and why is it classified as a LOLBin?
ruby is a legitimate, pre-installed or trusted utility on Linux. It is classified as a Living-off-the-Land Binary (LOLBin) because adversaries abuse its built-in functionality to perform malicious operations—such as Execute—without dropping custom malware binaries on disk.
How do threat actors abuse ruby in cyber intrusions?
Adversaries leverage ruby to execute stealthy actions while evading signature-based security controls. For example, attackers execute commands like "ruby -e 'exec "/bin/sh"'" to achieve Execute, masquerading behind legitimate system process lineage.
How can SOC analysts detect suspicious ruby activity?
Detection engineers monitor process creation events (Windows Event ID 4688 or Sysmon Event ID 1; Linux auditd EXECVE; macOS Endpoint Security) inspecting anomalous command line arguments, unusual parent-child process relationships (e.g. Office apps or web servers spawning ruby), and unexpected network connections.
What MITRE ATT&CK techniques does ruby map to?
ruby maps to MITRE ATT&CK technique(s): T1059. These techniques cover adversary actions across tactics such as Defense Evasion, Execution, Persistence, and Command and Control.
How can organizations mitigate and restrict ruby?
Mitigation strategies include implementing Application Control policies (AppLocker or Windows Defender Application Control - WDAC), enforcing Attack Surface Reduction (ASR) rules, configuring strict privilege separation (disallowing standard users from running sensitive switches), and alerting on execution from non-standard directories.
Other High-Traffic LINUX LOLBins
Find searches directory trees for files matching criteria. When configured with SUID permissions or sudo privileges without restrictions, its -exec flag can spawn root shells or execute arbitrary commands.
Curl is a tool to transfer data from or to a server using supported protocols (HTTP, HTTPS, FTP, etc.). Attackers leverage curl to download malicious second-stage scripts and pipe directly into bash or sh for fileless in-memory execution.
The GNU Bourne Again SHell (bash) is the default interactive shell on most Linux distributions. Abused for spawning interactive reverse TCP shells, executing encoded base64 commands, and privilege escalation.
Socat is a command-line based utility that establishes two bidirectional byte streams and transfers data between them. Attackers use socat to establish encrypted TTY reverse shells and tunnel traffic across isolated network zones.