CVE-2019-25358: FileOptimizer DOS Vulnerability

CVE-2019-25358 Overview

CVE-2019-25358 is a denial of service vulnerability affecting FileOptimizer version 14.00.2524, a popular file optimization utility. The vulnerability allows attackers to crash the application by manipulating the FileOptimizer32.ini configuration file. Specifically, attackers can overwrite the TempDirectory parameter with an excessively long 5000-character buffer, causing the application to crash when a user attempts to open the options dialog.

Critical Impact

Attackers can render FileOptimizer unusable by corrupting the configuration file, causing persistent application crashes and denial of service conditions for affected users.

Affected Products

• FileOptimizer 14.00.2524

Discovery Timeline

• 2026-02-18 - CVE CVE-2019-25358 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2019-25358

Vulnerability Analysis

This vulnerability is classified under CWE-1282, which relates to improper handling of input that leads to denial of service conditions. The flaw exists within FileOptimizer's configuration file parsing mechanism, where the application fails to properly validate the length of the TempDirectory parameter value before processing it.

When FileOptimizer reads its configuration from FileOptimizer32.ini, it does not implement adequate boundary checks on the string values. An attacker who can modify this configuration file can insert an oversized buffer value (approximately 5000 characters) for the TempDirectory setting. When the user subsequently opens the application's options dialog, the excessive input triggers a crash condition.

The network attack vector indicates that this vulnerability could potentially be exploited through scenarios where an attacker can remotely manipulate the configuration file, such as through shared network drives, synchronized cloud storage, or other file-sharing mechanisms.

Root Cause

The root cause of this vulnerability is improper input validation in the configuration file parsing routine. FileOptimizer does not enforce maximum length restrictions on configuration parameter values before loading them into memory. When the TempDirectory parameter contains a 5000-character string, the application cannot properly handle this oversized input, resulting in a buffer-related crash condition.

Attack Vector

The attack vector involves modifying the FileOptimizer32.ini configuration file to include an excessively long string value for the TempDirectory parameter. This can be accomplished through several means:

1. Direct file system access where the attacker can write to the user's configuration directory
2. Social engineering to trick users into replacing their configuration file with a malicious version
3. Exploiting other vulnerabilities that provide write access to the file system
4. Targeting shared environments where configuration files may be accessible across network shares

Once the malicious configuration is in place, the application will crash whenever the user attempts to access the options menu, effectively denying service until the corrupted configuration is removed or repaired.

Detection Methods for CVE-2019-25358

Indicators of Compromise

• Presence of unusually large FileOptimizer32.ini files (significantly larger than typical configuration size)
• The TempDirectory parameter containing thousands of characters instead of a normal directory path
• Repeated FileOptimizer application crashes when attempting to access options

Detection Strategies

• Monitor for file modifications to FileOptimizer32.ini configuration files, especially changes that significantly increase file size
• Implement file integrity monitoring to detect unauthorized modifications to application configuration files
• Review system event logs for repeated application crash events related to FileOptimizer

Monitoring Recommendations

• Deploy endpoint monitoring solutions to track modifications to critical application configuration files
• Configure alerts for FileOptimizer crash events that may indicate exploitation attempts
• Use SentinelOne's behavioral AI engine to detect anomalous file modification patterns targeting application configurations

How to Mitigate CVE-2019-25358

Immediate Actions Required

• Verify the integrity of FileOptimizer32.ini configuration files on affected systems
• Remove or restore any corrupted configuration files to their default state
• Restrict write permissions to configuration file directories where possible
• Consider upgrading to a newer version of FileOptimizer if available

Patch Information

Refer to the SourceForge Project Overview for the latest FileOptimizer releases and any available security updates. The VulnCheck Advisory for FileOptimizer provides additional details on this vulnerability.

Technical details and proof-of-concept information can be found in Exploit-DB #47586.

Workarounds

• Set read-only permissions on FileOptimizer32.ini after configuring the application to prevent unauthorized modifications
• Backup the configuration file regularly and monitor for unexpected changes
• Run FileOptimizer in a restricted environment with limited file system write access
• Consider using application whitelisting to prevent unauthorized modifications to configuration directories

# Configuration example - Set read-only permissions on Windows
attrib +r "%APPDATA%\FileOptimizer\FileOptimizer32.ini"

# On Unix-like systems (if applicable)
chmod 444 ~/.config/FileOptimizer/FileOptimizer32.ini