CVE-2018-25285: Fathom 2.4 Buffer Overflow Vulnerability

CVE-2018-25285 Overview

CVE-2018-25285 is a buffer overflow vulnerability in Fathom 2.4, a data analysis and modeling software. The vulnerability exists in the Authorization Code field and allows local attackers to crash the application by submitting an oversized input string. Attackers can paste a 6000-byte payload into the Authorization Code field and click Activate to trigger a denial of service condition.

Critical Impact

Local attackers can cause a complete denial of service by crashing the Fathom application through buffer overflow exploitation in the Authorization Code input field.

Affected Products

• Fathom 2.4

Discovery Timeline

• 2026-04-26 - CVE CVE-2018-25285 published to NVD
• 2026-04-27 - Last updated in NVD database

Technical Details for CVE-2018-25285

Vulnerability Analysis

This vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), commonly known as a classic buffer overflow. The application fails to properly validate the length of user-supplied input in the Authorization Code field before copying it to a fixed-size buffer. When a user provides an input string exceeding the expected buffer size (approximately 6000 bytes), the application writes beyond the allocated memory boundary, corrupting adjacent memory and causing the application to crash.

The local attack vector requires user interaction, as the attacker must have access to the application interface and manually trigger the overflow by pasting the oversized payload and clicking the Activate button. While this limits the attack surface compared to remote exploitation, it still poses a significant availability risk in multi-user environments or scenarios where social engineering could be employed.

Root Cause

The root cause of this vulnerability is inadequate input validation and bounds checking in the Authorization Code processing functionality. The application allocates a fixed-size buffer for the authorization code but does not verify that user input fits within this allocation before performing the copy operation. This classic programming error allows attackers to overflow the buffer with excessive data.

Attack Vector

The attack requires local access to the Fathom application. An attacker with access to the software can exploit this vulnerability by:

1. Opening the Fathom 2.4 application
2. Navigating to the Authorization Code input field
3. Pasting a crafted payload of approximately 6000 bytes or more
4. Clicking the Activate button to trigger the buffer overflow

The vulnerability results in a denial of service condition where the application crashes. According to the Exploit-DB entry #45294, this attack has been publicly documented and proof-of-concept code is available.

Detection Methods for CVE-2018-25285

Indicators of Compromise

• Unexpected Fathom application crashes or termination events
• Application crash dumps or error logs indicating memory access violations
• Unusually large input values in authorization-related log entries
• Multiple consecutive application restarts in a short time period

Detection Strategies

• Monitor for Fathom application crashes with memory corruption signatures
• Implement application-level logging to capture authorization code input lengths
• Deploy endpoint detection and response (EDR) solutions to identify abnormal application behavior
• Enable Windows Error Reporting to capture crash details for forensic analysis

Monitoring Recommendations

• Configure system monitoring to alert on repeated Fathom process terminations
• Implement file integrity monitoring on Fathom application directories
• Monitor for suspicious user activity around the authorization workflow
• Review application event logs for buffer overflow-related error codes

How to Mitigate CVE-2018-25285

Immediate Actions Required

• Restrict access to Fathom 2.4 to trusted users only
• Consider removing Fathom 2.4 if it is not essential for business operations
• Implement application whitelisting to prevent unauthorized modifications
• Monitor the Concord Fathom download page for updated versions

Patch Information

No vendor patch information is currently available in the CVE data. Users should monitor the official Concord Fathom website for security updates. The VulnCheck advisory may provide additional remediation guidance.

Workarounds

• Limit user access to the Fathom application to prevent unauthorized exploitation
• Implement input validation at the network or application layer if possible
• Consider deploying the application in an isolated environment to limit impact
• Use endpoint protection solutions that can detect and prevent buffer overflow attacks

# Configuration example
# Restrict Fathom application access to specific users (Windows)
# Use Local Security Policy or Group Policy to limit access
icacls "C:\Program Files\Fathom" /grant:r "DOMAIN\TrustedUsers:(RX)"
icacls "C:\Program Files\Fathom" /deny "DOMAIN\Domain Users:(X)"