CVE-2016-20038: yTree Buffer Overflow Vulnerability

CVE-2016-20038 Overview

CVE-2016-20038 is a stack-based buffer overflow vulnerability affecting yTree version 1.94-1.1, a file manager utility for Unix-like systems. The vulnerability allows local attackers to execute arbitrary code by supplying an excessively long argument to the application. When exploited, attackers can craft a malicious command-line argument containing shellcode and a return address to overwrite the stack and execute code in the application context.

Critical Impact

Local attackers can achieve arbitrary code execution through stack buffer overflow exploitation, potentially gaining full control of the affected system with the privileges of the yTree process.

Affected Products

• yTree 1.94-1.1

Discovery Timeline

• 2026-03-28 - CVE-2016-20038 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2016-20038

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), specifically manifesting as a stack-based buffer overflow. The flaw exists in how yTree handles command-line arguments without proper bounds checking. When a user provides an argument that exceeds the expected buffer size, the application fails to validate the input length before copying it to a fixed-size stack buffer.

The local attack vector requires the attacker to have access to the target system to execute the yTree binary with crafted arguments. No user interaction or special privileges are required beyond the ability to run the application, making this vulnerability accessible to any local user on systems where yTree is installed.

Root Cause

The vulnerability stems from improper input validation when processing command-line arguments. The application allocates a fixed-size buffer on the stack to store user-supplied input but does not enforce length restrictions before copying data into this buffer. This classic buffer overflow pattern allows attackers to write beyond the allocated buffer boundaries, corrupting adjacent stack memory including saved return addresses.

Attack Vector

Exploitation involves passing an oversized argument to the yTree application. The attacker constructs a payload that includes padding to reach the saved return address on the stack, followed by a controlled address pointing to attacker-supplied shellcode. When the vulnerable function returns, program execution is redirected to the shellcode, enabling arbitrary code execution.

The attack is executed locally through command-line interaction with the yTree binary. Successful exploitation grants the attacker code execution with the same privileges as the yTree process. Public exploit code is available through Exploit-DB #39406, which demonstrates the buffer overflow exploitation technique.

Detection Methods for CVE-2016-20038

Indicators of Compromise

• Unusual yTree process crashes or core dumps indicating potential exploitation attempts
• Abnormally long command-line arguments passed to the yTree binary in process logs
• Unexpected child processes spawned from yTree execution
• Suspicious shell activity following yTree execution on the system

Detection Strategies

• Monitor process execution logs for yTree invocations with unusually long arguments exceeding normal operational parameters
• Implement application whitelisting to track and alert on unexpected yTree binary usage
• Deploy endpoint detection solutions capable of identifying buffer overflow exploitation patterns
• Use stack canary detection mechanisms to identify stack smashing attempts

Monitoring Recommendations

• Enable audit logging for command-line arguments passed to applications on critical systems
• Configure intrusion detection systems to alert on known exploitation signatures
• Review system logs for unexpected process behavior associated with yTree execution
• Monitor for unauthorized privilege escalation following yTree process execution

How to Mitigate CVE-2016-20038

Immediate Actions Required

• Remove or restrict access to vulnerable yTree 1.94-1.1 installations on affected systems
• Limit execution privileges for yTree to only authorized users who require the functionality
• Consider replacing yTree with alternative file management utilities that are actively maintained
• Apply operating system-level protections such as ASLR and stack canaries to mitigate exploitation

Patch Information

Users should check the official yTree website for updated versions that may address this vulnerability. If no patched version is available, consider discontinuing use of the affected software or implementing compensating controls. Additional technical details are available in the VulnCheck Advisory.

Workarounds

• Restrict yTree binary execution permissions using file system access controls to authorized users only
• Deploy application sandboxing to contain potential exploitation within isolated environments
• Enable operating system exploit mitigations including DEP/NX, ASLR, and stack protector features
• Consider using wrapper scripts that validate and sanitize command-line argument lengths before passing to yTree

# Example: Restrict yTree execution permissions
chmod 750 /usr/bin/ytree
chown root:trusted-users /usr/bin/ytree