CVE-2019-25268: NREL BEopt DLL Hijacking Vulnerability

CVE-2019-25268 Overview

CVE-2019-25268 is a DLL hijacking vulnerability affecting NREL BEopt version 2.8.0.0, a building energy optimization tool developed by the National Renewable Energy Laboratory. The vulnerability allows attackers to execute arbitrary code by exploiting insecure library loading mechanisms when users open application files from remote network shares.

The vulnerability occurs due to the application's improper handling of DLL search order, specifically affecting sdl2.dll and libegl.dll libraries. An attacker can place malicious versions of these DLLs on WebDAV or SMB shares, which are then loaded and executed when a victim opens a legitimate BEopt application file from the compromised share.

Critical Impact

Successful exploitation enables remote code execution through social engineering, allowing attackers to execute arbitrary code with the privileges of the user running BEopt.

Affected Products

• NREL BEopt 2.8.0.0
• Applications loading sdl2.dll from untrusted paths
• Applications loading libegl.dll from untrusted paths

Discovery Timeline

• 2026-01-08 - CVE CVE-2019-25268 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2019-25268

Vulnerability Analysis

This vulnerability falls under CWE-427 (Uncontrolled Search Path Element), a class of weakness where software uses a search path that includes directories outside of the application's direct control. In the case of BEopt 2.8.0.0, the application fails to specify absolute paths when loading dependent DLLs, instead relying on the Windows DLL search order.

When a user opens a BEopt project file (.beopt or related file types) from a network share, the application searches for required DLLs in the current working directory before checking system directories. This behavior allows an attacker to plant malicious copies of sdl2.dll and libegl.dll alongside seemingly legitimate project files on a WebDAV or SMB share.

The attack requires user interaction—the victim must be convinced to open a file from an attacker-controlled network location. However, this is a common attack vector in enterprise environments where users regularly access shared resources.

Root Cause

The root cause is the application's failure to implement safe DLL loading practices. BEopt 2.8.0.0 does not use absolute paths when loading sdl2.dll and libegl.dll, nor does it restrict the DLL search path to trusted directories only. The Windows DLL search order includes the directory from which the application was loaded (or in some cases, the current working directory), making it susceptible to hijacking when files are opened from untrusted locations.

Modern secure coding practices recommend using functions like SetDllDirectory() or SetDefaultDllDirectories() to restrict the search path, or loading DLLs with absolute paths to prevent this class of vulnerability.

Attack Vector

The attack is network-based and requires user interaction. An attacker crafts a malicious scenario by:

1. Creating or obtaining a legitimate BEopt project file
2. Placing the project file on an attacker-controlled WebDAV or SMB share
3. Adding malicious sdl2.dll and/or libegl.dll files to the same directory
4. Social engineering the victim to open the project file from the network share

When the victim opens the project file, Windows loads the malicious DLLs from the network share directory instead of the legitimate libraries from the application's installation directory. The malicious code executes with the user's privileges, potentially enabling data theft, persistence mechanisms, or lateral movement within the network.

Detection Methods for CVE-2019-25268

Indicators of Compromise

• Unexpected DLL files named sdl2.dll or libegl.dll in network share directories alongside BEopt project files
• BEopt.exe loading DLLs from network paths (SMB or WebDAV) rather than the application installation directory
• Process creation events showing BEopt spawning unexpected child processes after loading from network locations

Detection Strategies

• Monitor for DLL loading events where the path contains network indicators (\\ for SMB or http:// for WebDAV) and the DLL names match sdl2.dll or libegl.dll
• Deploy endpoint detection rules to alert on BEopt.exe loading DLLs from directories outside %ProgramFiles%\BEopt or similar expected installation paths
• Use application whitelisting solutions to prevent unauthorized DLL loading in sensitive environments

Monitoring Recommendations

• Enable Windows Sysmon with configurations tracking DLL load events (Event ID 7) for BEopt.exe
• Configure network monitoring to detect suspicious WebDAV or SMB traffic involving DLL files
• Implement user behavior analytics to identify unusual access patterns to network shares containing executable content

How to Mitigate CVE-2019-25268

Immediate Actions Required

• Avoid opening BEopt project files directly from network shares, especially WebDAV or SMB locations from untrusted sources
• Copy project files to local storage before opening them with BEopt
• Implement Group Policy settings to restrict DLL loading from network paths
• Consider application sandboxing or virtualization for running BEopt in environments where network file access is necessary

Patch Information

No official patch information is currently available from NREL for this vulnerability. Organizations using BEopt 2.8.0.0 should implement the recommended workarounds and monitor vendor communications for security updates. Additional technical details are available through CXSecurity Issue WLB-2019030108, IBM X-Force Vulnerability #158065, and ZeroScience Vulnerability ZSL-2019-5513.

Workarounds

• Configure Windows to require SMB signing and disable WebDAV if not required in the enterprise environment
• Use Software Restriction Policies or AppLocker to prevent DLL execution from network locations
• Implement network segmentation to limit access to untrusted file shares from workstations running BEopt
• Train users to recognize social engineering attempts involving network-hosted files