>tar
GNU tar is an archiving utility. Attackers abuse tar checkpoint execution options (--checkpoint-action=exec) to spawn an interactive shell or execute arbitrary commands when running with sudo or SUID permissions.
Default Executable Paths
/usr/bin/tar/bin/tarIntegrity & Metadata
Checkpoint actions in tar allow running arbitrary commands periodically during archive processing, frequently abused in wildcards or automated backup scripts.
Monitor process creation of tar containing "--checkpoint" and "--checkpoint-action=exec".
Executive Summary & AI Quick Reference
tar is a native utility pre-installed on Linux systems. Threat actors and red teams abuse tar 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.
Abuses GNU tar checkpoint parameters to spawn an interactive shell.
tar -cf /dev/null /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/shSIEM & EDR Detection Rules
Production telemetry rules configured for Microsoft Defender, Sigma, and Splunk.
Telemetry & SIEM Detection Suite (tar)
Validated against MITRE T1059.004, T1548.0011DeviceProcessEvents | where FileName =~ "tar" | where ProcessCommandLine has_all ("--checkpoint", "--checkpoint-action=exec") | project Timestamp, DeviceName, AccountName, ProcessCommandLineMitigation, Hardening & Prevention
Recommended defensive controls to block or constrain tar abuse.
Audit and remove unnecessary SUID / SGID bits (`chmod u-s /path/to/$tar`) and restrict sudoers NOPASSWD execution grants.
Implement AppArmor or SELinux profiles restricting tar 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) • tar
Key operational questions and defensive answers about tar LOLBin tradecraft.
What is tar and why is it classified as a LOLBin?
tar 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 tar in cyber intrusions?
Adversaries leverage tar to execute stealthy actions while evading signature-based security controls. For example, attackers execute commands like "tar -cf /dev/null /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/sh" to achieve Execute, masquerading behind legitimate system process lineage.
How can SOC analysts detect suspicious tar 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 tar), and unexpected network connections.
What MITRE ATT&CK techniques does tar map to?
tar maps to MITRE ATT&CK technique(s): T1059.004, T1548.001. These techniques cover adversary actions across tactics such as Defense Evasion, Execution, Persistence, and Command and Control.
How can organizations mitigate and restrict tar?
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.
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