CVE-2024-12476: Web Designer XML External Entity Flaw

CVE-2024-12476 Overview

CVE-2024-12476 is an XML External Entity (XXE) vulnerability [CWE-611] affecting the Web Designer configuration tool referenced in Schneider Electric security advisory SEVD-2025-014-04. An attacker who convinces a user to import a specially crafted XML file into the Web Designer configuration tool can trigger external entity resolution. Successful exploitation can lead to information disclosure, loss of workstation integrity, and potential remote code execution on the compromised computer.

Critical Impact
Importing a malicious XML file into the Web Designer tool can disclose local files, compromise workstation integrity, and enable code execution on the affected engineering workstation.

Affected Products

Schneider Electric Web Designer configuration tool (see SEVD-2025-014-04)
Engineering workstations running the affected Web Designer software
Systems where users import third-party or externally sourced XML configuration files

Discovery Timeline

2025-01-17 - CVE-2024-12476 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-12476

Vulnerability Analysis

The flaw is an Improper Restriction of XML External Entity Reference weakness [CWE-611] in the XML parsing routine used by the Web Designer configuration tool. When the tool imports an XML file, the underlying parser resolves external entities defined in the file's Document Type Definition (DTD). An attacker controls those entity references by crafting the XML input before it reaches the operator.

Because the parser resolves entities against the local file system and network resources, the imported document can force the tool to read sensitive files, contact attacker-controlled hosts, or process content that changes program behavior. The advisory also notes the impact extends to workstation integrity and remote code execution, indicating that entity resolution can influence downstream processing beyond simple file disclosure.

Exploitation requires local access to the Web Designer tool and user interaction to import the malicious XML file, which aligns with the attack vector described in the vendor advisory.

Root Cause

The XML parser used during configuration import does not disable or restrict external entity resolution. Standard hardening for XML parsers requires disabling DTDs and external entity processing before parsing untrusted input. The Web Designer import path fails to apply those restrictions, so any XML file supplied by an operator is processed with full entity expansion.

Attack Vector

An attacker delivers a crafted XML file to an engineer or operator through email, a shared file store, a project handoff, or a compromised repository. When the user opens the file in the Web Designer configuration tool, the parser resolves the attacker-defined entities. Depending on the payload, this can exfiltrate file contents via out-of-band channels, disclose data returned into the imported configuration, or drive execution flows that lead to code execution on the workstation.

Detailed exploitation mechanics are not published; refer to the Schneider Electric Security Notice SEVD-2025-014-04 for vendor-authoritative details.

Detection Methods for CVE-2024-12476

Indicators of Compromise

XML files submitted to engineering workstations containing <!DOCTYPE> declarations with SYSTEM or PUBLIC external entity references
Outbound network connections from the Web Designer process to unexpected hosts immediately after an XML import operation
Access by the Web Designer process to sensitive files such as hosts, credential stores, or user profile paths not required by normal configuration workflows
New processes spawned by the Web Designer application following an XML import

Detection Strategies

Inspect XML files imported into engineering tools for DTD declarations and external entity definitions before they reach operator workstations
Alert on process telemetry showing the Web Designer executable performing file reads outside its project directories or opening network sockets during import
Correlate user-initiated XML imports with unusual DNS lookups or HTTP requests from the workstation

Monitoring Recommendations

Log all XML file imports on engineering workstations and retain samples for retrospective analysis
Monitor egress traffic from OT engineering hosts to detect out-of-band exfiltration channels used by XXE payloads
Track child-process creation and file-access patterns of the Web Designer configuration tool with EDR telemetry

How to Mitigate CVE-2024-12476

Immediate Actions Required

Apply the fix described in Schneider Electric advisory SEVD-2025-014-04 to all affected Web Designer installations
Restrict imports in the Web Designer configuration tool to XML files from verified, trusted sources only
Segment engineering workstations from general corporate networks and the internet to limit out-of-band exfiltration paths
Train engineers and integrators to treat externally supplied XML project files as untrusted inputs

Patch Information

Schneider Electric published remediation guidance in the Schneider Electric Security Notice SEVD-2025-014-04. Review the advisory for the fixed version, upgrade instructions, and any interim compensating controls provided by the vendor.

Workarounds

Do not import XML configuration files received from untrusted or unverified sources into the Web Designer tool
Validate and sanitize XML files in an isolated review environment before importing them on production engineering workstations
Apply application allowlisting on engineering workstations so that unexpected processes spawned during XML import cannot execute
Block outbound connections from engineering workstations at the firewall to constrain exfiltration channels used by XXE payloads

bash

# Configuration example
# Refer to Schneider Electric advisory SEVD-2025-014-04 for vendor-supplied
# configuration and version guidance. No sanitized public exploit or
# hardening snippet is provided in the referenced sources.