CVE-2020-37139: Odin Secure FTP Expert DoS Vulnerability

CVE-2020-37139 Overview

CVE-2020-37139 is a local denial of service vulnerability affecting Odin Secure FTP Expert version 7.6.3. The vulnerability allows attackers to crash the application by manipulating site information fields. By pasting 108 bytes of repeated characters into connection fields, an attacker can trigger a buffer overflow condition that causes the application to become unresponsive and crash.

Critical Impact

Attackers with local access can repeatedly crash Odin Secure FTP Expert, disrupting FTP operations and potentially causing data loss during active file transfers.

Affected Products

• Odin Secure FTP Expert 7.6.3

Discovery Timeline

• 2026-02-05 - CVE-2020-37139 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2020-37139

Vulnerability Analysis

This vulnerability stems from improper resource allocation controls within the site information handling functionality of Odin Secure FTP Expert. The application fails to properly validate the length of user-supplied input in connection configuration fields before processing, leading to a denial of service condition.

The vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the application does not enforce appropriate boundaries on resource consumption when processing site information data. When an attacker provides exactly 108 bytes of repeated characters in the affected input fields, the application attempts to allocate memory without proper bounds checking, resulting in a buffer overflow that crashes the application.

This is a local attack vector, meaning an attacker requires local access to the system running the vulnerable FTP client. No authentication is required to exploit this vulnerability, though user interaction is necessary as the malicious input must be pasted into the application's interface.

Root Cause

The root cause of CVE-2020-37139 is the lack of input length validation in the site information processing routines. The application allocates a fixed-size buffer for connection field data but does not verify that user input conforms to expected size constraints before copying data into this buffer. This allows an attacker to overflow the buffer with as few as 108 bytes of data, corrupting adjacent memory and causing the application to crash.

Attack Vector

The attack requires local access to a system running Odin Secure FTP Expert 7.6.3. An attacker must interact with the application's user interface to input malicious data into the site information fields. The exploitation process involves:

1. Opening the Odin Secure FTP Expert application
2. Navigating to the site configuration or connection settings
3. Pasting 108 or more bytes of repeated characters into a vulnerable input field
4. Triggering the overflow when the application processes the input

The vulnerability is documented in an Exploit-DB entry which provides additional technical details about the exploitation technique.

Detection Methods for CVE-2020-37139

Indicators of Compromise

• Unexpected crashes of the Odin Secure FTP Expert application process
• Application event logs showing memory access violations or buffer overflow exceptions
• Repeated restarts of the FTP client application in a short time period

Detection Strategies

• Monitor for Windows application crash events (Event ID 1000) associated with the Odin Secure FTP Expert executable
• Implement endpoint detection rules to identify repeated application crashes that may indicate exploitation attempts
• Deploy application whitelisting to prevent unauthorized access to the vulnerable FTP client

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash dump data for forensic analysis
• Configure SIEM rules to alert on patterns of repeated application crashes on systems running Odin Secure FTP Expert
• Review endpoint telemetry for unusual process termination events associated with FTP client software

How to Mitigate CVE-2020-37139

Immediate Actions Required

• Restrict local access to systems running Odin Secure FTP Expert 7.6.3 to trusted users only
• Consider migrating to an alternative FTP client with active security support
• Implement application-level sandboxing to limit the impact of crashes on system stability
• Backup any saved FTP site configurations before removal or migration

Patch Information

No vendor patch is currently available for this vulnerability. The affected software, Odin Secure FTP Expert, appears to be legacy software without active maintenance. Organizations are advised to migrate to actively supported FTP client alternatives. Additional information about the vulnerability can be found in the VulnCheck Security Advisory.

Workarounds

• Limit user permissions to prevent untrusted users from accessing the FTP client configuration interface
• Deploy endpoint protection solutions capable of detecting and preventing buffer overflow attacks
• Consider using network-level FTP solutions that do not require local client software on user workstations
• Implement application control policies to restrict clipboard operations to the vulnerable application

# Example: Restrict application access using Windows AppLocker
# Create a rule to limit which users can execute the vulnerable application
New-AppLockerPolicy -RuleType Path -Path "C:\Program Files\Odin Secure FTP Expert\*" `
  -User "DOMAIN\FTP-Authorized-Users" -Action Allow