CVE-2018-25267: UltraISO Buffer Overflow Vulnerability

CVE-2018-25267 Overview

CVE-2018-25267 is a local buffer overflow vulnerability affecting UltraISO version 9.7.1.3519. The vulnerability exists in the Output FileName field of the Make CD/DVD Image dialog, where improper input validation allows attackers to overflow a fixed-size buffer. By crafting a malicious filename string containing 304 bytes of data followed by carefully positioned SEH (Structured Exception Handler) record overwrite values, attackers can corrupt the application's exception handling mechanism, leading to application crashes and potential denial of service conditions.

Critical Impact

Local attackers can crash UltraISO by pasting a specially crafted filename string into the Output FileName field, causing buffer overflow and SEH corruption that results in denial of service.

Affected Products

• UltraISO 9.7.1.3519
• UltraISO prior versions may also be affected

Discovery Timeline

• 2026-04-22 - CVE CVE-2018-25267 published to NVD
• 2026-04-22 - Last updated in NVD database

Technical Details for CVE-2018-25267

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption vulnerability that occurs when the application writes data beyond the boundaries of an allocated buffer. The flaw resides in how UltraISO handles user-supplied input in the Output FileName field within the Make CD/DVD Image dialog interface.

When a user enters or pastes a filename into this field, the application fails to properly validate the length of the input before copying it into a fixed-size buffer. This lack of boundary checking allows an attacker to supply an oversized input string that overwrites adjacent memory locations, including critical exception handling structures.

The attack requires local access to the system and user interaction to paste the malicious payload into the vulnerable field. Upon triggering the overflow, the application's SEH chain becomes corrupted, causing UltraISO to crash when an exception occurs.

Root Cause

The root cause of CVE-2018-25267 is insufficient input validation in the Output FileName field handler within UltraISO. The application allocates a fixed-size buffer for storing the filename but does not enforce proper length checks when copying user input into this buffer. This allows data exceeding the buffer's capacity to overflow into adjacent memory regions, corrupting the SEH and SE handler records stored on the stack.

Attack Vector

The attack vector is local and requires the attacker to have access to the target system where UltraISO is installed. The exploitation process involves:

1. Opening UltraISO and navigating to the Make CD/DVD Image dialog
2. Crafting a malicious string consisting of 304 bytes of padding data
3. Appending specific values designed to overwrite the SEH record
4. Pasting the crafted payload into the Output FileName field
5. Triggering an exception condition that causes the corrupted exception handler to execute

The vulnerability enables stack-based buffer overflow attacks that corrupt the application's exception handling mechanism. While the immediate impact is denial of service through application crash, similar vulnerabilities historically have been leveraged for code execution when DEP and ASLR protections can be bypassed. Technical details regarding exploitation techniques are documented in the Exploit-DB #45996 advisory.

Detection Methods for CVE-2018-25267

Indicators of Compromise

• UltraISO application crashes with access violation errors related to exception handling
• Windows Event Logs showing UltraISO.exe application faults with exception code 0xC0000005
• Clipboard activity containing unusually long strings (300+ bytes) when UltraISO is running
• Stack traces indicating SEH chain corruption in UltraISO processes

Detection Strategies

• Monitor for UltraISO application crashes and analyze crash dumps for buffer overflow indicators
• Implement endpoint detection rules to identify attempts to paste excessively long strings into UltraISO dialogs
• Deploy application behavior monitoring to detect unusual memory access patterns in UltraISO.exe
• Use SentinelOne's behavioral AI to detect exploitation attempts targeting Windows SEH mechanisms

Monitoring Recommendations

• Enable Windows Error Reporting and collect crash dumps for forensic analysis
• Configure SIEM alerts for repeated UltraISO crashes on the same endpoint
• Monitor file system activity for creation of malicious filename strings or exploit payloads
• Review user activity logs for clipboard operations involving long character sequences

How to Mitigate CVE-2018-25267

Immediate Actions Required

• Update UltraISO to the latest available version from the UltraISO Official Website
• Restrict access to UltraISO to trusted users only on shared systems
• Consider using alternative ISO imaging software if patches are unavailable
• Implement application whitelisting to prevent unauthorized UltraISO execution

Patch Information

Check the UltraISO Official Website for the latest version that addresses this vulnerability. The VulnCheck Advisory on UltraISO provides additional guidance on remediation steps.

Workarounds

• Avoid copying and pasting untrusted content into UltraISO dialog fields
• Run UltraISO with least-privilege user accounts to limit the impact of exploitation
• Enable Windows DEP (Data Execution Prevention) and ASLR to make exploitation more difficult
• Consider running UltraISO in an isolated environment or virtual machine for sensitive operations

# Enable DEP for all applications via Windows command line
bcdedit /set nx AlwaysOn

# Verify DEP status
wmic OS Get DataExecutionPrevention_SupportPolicy