>tail
Tail outputs the last part of files. SUID tail allows standard users to read protected credentials, tokens, and audit log entries.
Default Executable Paths
/usr/bin/tail/bin/tailIntegrity & Metadata
SUID tail is functionally identical to head for unauthorized file disclosure.
Alert on tail processes referencing /etc/shadow or protected directories.
Executive Summary & AI Quick Reference
tail is a native utility pre-installed on Linux systems. Threat actors and red teams abuse tail as a Living-off-the-Land Binary (LOLBin) to achieve Credential Dump 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.
Reads the entire contents of /etc/shadow from line 1 onwards.
tail -n +1 /etc/shadowSIEM & EDR Detection Rules
Production telemetry rules configured for Microsoft Defender, Sigma, and Splunk.
Telemetry & SIEM Detection Suite (tail)
Validated against MITRE T10051DeviceProcessEvents | where FileName =~ "tail" | where ProcessCommandLine has_any ("/etc/shadow", "/etc/sudoers", "id_rsa") | project Timestamp, DeviceName, AccountName, ProcessCommandLineMitigation, Hardening & Prevention
Recommended defensive controls to block or constrain tail abuse.
Audit and remove unnecessary SUID / SGID bits (`chmod u-s /path/to/$tail`) and restrict sudoers NOPASSWD execution grants.
Implement AppArmor or SELinux profiles restricting tail 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) • tail
Key operational questions and defensive answers about tail LOLBin tradecraft.
What is tail and why is it classified as a LOLBin?
tail 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 Credential Dump—without dropping custom malware binaries on disk.
How do threat actors abuse tail in cyber intrusions?
Adversaries leverage tail to execute stealthy actions while evading signature-based security controls. For example, attackers execute commands like "tail -n +1 /etc/shadow" to achieve Credential Dump, masquerading behind legitimate system process lineage.
How can SOC analysts detect suspicious tail 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 tail), and unexpected network connections.
What MITRE ATT&CK techniques does tail map to?
tail maps to MITRE ATT&CK technique(s): T1005. These techniques cover adversary actions across tactics such as Defense Evasion, Execution, Persistence, and Command and Control.
How can organizations mitigate and restrict tail?
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.