CVE-2019-25330: SurfOffline Professional DoS Vulnerability

CVE-2019-25330 Overview

CVE-2019-25330 is a Stack-based Buffer Overflow vulnerability (CWE-121) affecting SurfOffline Professional 2.2.0.103. The application contains a structured exception handler (SEH) overflow vulnerability that allows attackers to crash the application by manipulating the project name input. An attacker can craft a malicious payload consisting of 382 'A' characters followed by specific byte sequences to trigger a denial of service condition and overwrite SEH registers.

Critical Impact

Local attackers can exploit this vulnerability to cause application crashes through SEH register overwrites, resulting in denial of service conditions for users of the affected offline browser software.

Affected Products

• SurfOffline Professional version 2.2.0.103
• BimeSoft SurfOffline offline browser application

Discovery Timeline

• 2026-02-12 - CVE CVE-2019-25330 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2019-25330

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow), which occurs when a program writes data beyond the allocated boundary of a stack buffer. In the case of SurfOffline Professional, the vulnerability specifically targets the Structured Exception Handler (SEH) mechanism in Windows applications.

The SEH is a Windows mechanism designed to handle runtime exceptions. When exploited, an attacker can overwrite the SEH chain pointer stored on the stack, potentially gaining control of program execution flow. The attack requires local access and user interaction, as the victim must open a maliciously crafted project file.

The exploitation technique involves sending exactly 382 bytes of padding followed by carefully crafted byte sequences that overwrite the SEH records. This classic SEH-based overflow technique has been documented in the security community for years and represents a fundamental memory safety issue in the application's input handling routines.

Root Cause

The root cause of this vulnerability lies in improper input validation and boundary checking when processing the project name field within SurfOffline Professional. The application fails to properly validate the length of user-supplied input before copying it to a fixed-size stack buffer, allowing an attacker to write beyond the allocated memory space and corrupt the SEH chain.

Attack Vector

The attack vector is local, requiring an attacker to either have direct access to the target system or to social engineer a victim into opening a malicious project file. The exploitation process involves:

1. Creating a crafted project file with an oversized project name field
2. The malicious payload contains 382 bytes of padding characters
3. Following the padding, specific byte sequences are appended to overwrite SEH handler pointers
4. When the application processes the malformed project name, the buffer overflow corrupts the SEH chain
5. Upon triggering an exception, the corrupted SEH handler causes the application to crash

The vulnerability has been documented in Exploit-DB #47795, which provides detailed technical information about the exploitation technique. Additional advisory information is available from VulnCheck SurfOffline Advisory.

Detection Methods for CVE-2019-25330

Indicators of Compromise

• Presence of SurfOffline Professional project files (.sop or similar) with abnormally large project name fields
• Application crash dumps indicating SEH corruption or access violations in SurfOffline.exe
• Suspicious project files containing repetitive character patterns (e.g., long strings of 'A' characters)

Detection Strategies

• Monitor for unexpected crashes of SurfOffline.exe with exception codes indicating stack corruption
• Implement file integrity monitoring to detect modified or malicious project files
• Deploy endpoint detection solutions capable of identifying classic SEH overflow exploitation attempts
• Use application whitelisting to prevent unauthorized execution of potentially vulnerable legacy software

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash telemetry from SurfOffline Professional
• Configure SIEM rules to alert on repeated application crashes from the same executable
• Monitor network shares and email attachments for suspicious SurfOffline project files
• Implement user education programs to warn against opening project files from untrusted sources

How to Mitigate CVE-2019-25330

Immediate Actions Required

• Discontinue use of SurfOffline Professional 2.2.0.103 if possible, as the vendor (BimeSoft) appears to be no longer active based on archived website information
• Restrict file system permissions to prevent unauthorized users from placing malicious project files
• Implement application sandboxing or virtualization when SurfOffline Professional must be used
• Deploy endpoint protection solutions with exploit mitigation capabilities

Patch Information

No official patch appears to be available for this vulnerability. The vendor BimeSoft's website is no longer accessible, suggesting the software may be abandoned. Organizations using this software should consider migrating to alternative offline browsing solutions. Additional software information can be found at SurfOffline Software Information.

Workarounds

• Run SurfOffline Professional with reduced privileges to limit the impact of potential exploitation
• Enable Windows Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) system-wide for additional exploit mitigation
• Only open project files from trusted and verified sources
• Consider using application compatibility shims to enforce additional security restrictions on legacy applications

# Enable DEP for all programs (Windows)
# Run in elevated Command Prompt
bcdedit /set nx AlwaysOn

# Verify DEP status
wmic OS Get DataExecutionPrevention_SupportPolicy