>gdb
GNU Debugger (gdb) allows code inspection and execution. When granted SUID permissions or privileged sudo rights, gdb can execute arbitrary shell commands prior to loading programs.
Default Executable Paths
/usr/bin/gdbIntegrity & Metadata
The -ex parameter in gdb executes specified debugger commands at launch, including shell escapes (!sh).
Detect gdb command lines containing "-ex" followed by shell invocations or child shell processes spawned by gdb.
Executive Summary & AI Quick Reference
gdb is a native utility pre-installed on Linux systems. Threat actors and red teams abuse gdb 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.
Executes an interactive shell command via gdb startup parameters.
gdb -nx -ex '!sh' -ex quitSIEM & EDR Detection Rules
Production telemetry rules configured for Microsoft Defender, Sigma, and Splunk.
Telemetry & SIEM Detection Suite (gdb)
Validated against MITRE T1059.004, T1548.0011DeviceProcessEvents | where FileName =~ "gdb" | where ProcessCommandLine has "-ex" and ProcessCommandLine has_any ("!sh", "!bash", "!/bin/sh") | project Timestamp, DeviceName, AccountName, ProcessCommandLineMitigation, Hardening & Prevention
Recommended defensive controls to block or constrain gdb abuse.
Audit and remove unnecessary SUID / SGID bits (`chmod u-s /path/to/$gdb`) and restrict sudoers NOPASSWD execution grants.
Implement AppArmor or SELinux profiles restricting gdb 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) • gdb
Key operational questions and defensive answers about gdb LOLBin tradecraft.
What is gdb and why is it classified as a LOLBin?
gdb 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 gdb in cyber intrusions?
Adversaries leverage gdb to execute stealthy actions while evading signature-based security controls. For example, attackers execute commands like "gdb -nx -ex '!sh' -ex quit" to achieve Execute, masquerading behind legitimate system process lineage.
How can SOC analysts detect suspicious gdb 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 gdb), and unexpected network connections.
What MITRE ATT&CK techniques does gdb map to?
gdb 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 gdb?
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
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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.