CVE-2026-2401

Executive Summary

CVE-2026-2401 is a vulnerability in Schneider Electric products that allows an attacker to cause the insertion of sensitive information into log files (CWE-532). The vulnerability is triggered when a Web Admin user executes a malicious file provided by an attacker. This can lead to the exposure of confidential information, such as credentials, session tokens, or internal system details, through the application's log files. The CVSS score is listed as 0.0, which is likely a placeholder or unassigned value. The vendor has confirmed a patch is available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a product-level vulnerability in Schneider Electric's Web Admin interface.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder or unassigned value. Based on the description, the vulnerability requires a Web Admin user to execute a malicious file, indicating a need for user interaction and high privileges. The impact is on confidentiality, as sensitive information is exposed. A reasonable CVSS vector would be: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N (Local Attack Vector, Low Attack Complexity, High Privileges Required, User Interaction Required, Unchanged Scope, High Confidentiality Impact, No Integrity Impact, No Availability Impact). This would result in a score of approximately 4.5 (Medium).

Threat Level: Medium. The attack requires a Web Admin user to be tricked into executing a malicious file, which limits the attack surface but can lead to significant information disclosure.

Deep Dive & Mechanics

The vulnerability is rooted in the Web Admin interface of Schneider Electric products. The application fails to sanitize or filter sensitive data before writing it to log files. An attacker can craft a malicious file that, when executed by a Web Admin user, causes the application to log sensitive information (e.g., passwords, API keys, internal IP addresses) into the log file. The attacker can then access these logs (if they have read access to the file system or if logs are exposed through another vulnerability) to retrieve the confidential data.

The attack flow is as follows:

1. The attacker crafts a malicious file (e.g., a script, configuration file, or specially crafted input).
2. The attacker delivers the file to a Web Admin user (e.g., via email, file upload, or social engineering).
3. The Web Admin user executes the file within the Web Admin interface.
4. The application processes the file and, due to the vulnerability, logs sensitive information (e.g., the contents of the file, error messages containing secrets, or debug output).
5. The attacker gains access to the log file (e.g., through a separate vulnerability, misconfigured permissions, or by exploiting the same user's session) and extracts the sensitive information.

Vulnerable vs. Patched Code

No specific code snippets are available. The vulnerability is in the logging mechanism of the Web Admin interface. The vulnerable code likely logs all input or error details without filtering. The patched code would sanitize log entries to remove or mask sensitive information before writing to the log file.

Vulnerable Code (Conceptual):

def process_file(file_path):
    try:
        # Process the file
        data = open(file_path).read()
        # ... processing logic ...
    except Exception as e:
        # Vulnerable: logs the full error and file content
        log.error(f"Error processing file: {e}, File content: {data}")

Patched Code (Conceptual):

def process_file(file_path):
    try:
        # Process the file
        data = open(file_path).read()
        # ... processing logic ...
    except Exception as e:
        # Patched: logs only a generic message, no sensitive data
        log.error(f"Error processing file: {e}")
        # Optionally, log a sanitized version
        sanitized_data = sanitize_sensitive_data(data)
        log.debug(f"Sanitized file content: {sanitized_data}")

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Access to a Schneider Electric Web Admin interface.
• Ability to deliver a malicious file to a Web Admin user (e.g., via email, file upload, or social engineering).
• The Web Admin user must execute the file.

Exploitation Steps:

1. Craft the Malicious File: Create a file that, when processed by the Web Admin interface, triggers the logging of sensitive information. For example, a file containing a specially crafted string that causes the application to log its own credentials or internal configuration.

   # malicious_file.txt
   # This file contains a string that triggers verbose logging
   admin_password = "SuperSecretPassword123!"
   

2. Deliver the File: Send the file to a Web Admin user via email, a file upload feature, or by tricking them into downloading it from a compromised site.
3. Execute the File: The Web Admin user must execute the file within the Web Admin interface (e.g., by uploading it, running a script, or opening it in a configuration tool).
4. Retrieve the Logs: Access the log file (e.g., /var/log/schneider/webadmin.log) to extract the sensitive information.

Example Log Entry (Vulnerable):

[2026-01-15 10:30:45] ERROR: Error processing file: admin_password = "SuperSecretPassword123!"

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual file uploads or executions by Web Admin users.
• Monitor log files for unexpected sensitive data (e.g., passwords, API keys).
• Use the detection rules provided in the Detection Engineering section.

Mitigation:

• Apply the vendor patch immediately.
• Restrict access to log files to only authorized personnel.
• Implement log monitoring and alerting for sensitive data exposure.
• Train Web Admin users to be cautious of executing files from untrusted sources.

Indicators of Compromise (IOCs)

• Log File Entries: Log entries containing sensitive data such as passwords, API keys, or internal IP addresses.
• File Hashes: Hashes of known malicious files used to exploit this vulnerability (none publicly available).
• Network Traffic: Unusual outbound connections from the Web Admin server to attacker-controlled IPs (if logs are exfiltrated).
• Process Anomalies: Unexpected processes or scripts executed by the Web Admin user.

Detection Engineering

YARA Rule

rule CVE_2026_2401_Sensitive_Data_Logging {
    meta:
        description = "Detects log entries containing sensitive data indicative of CVE-2026-2401 exploitation"
        author = "Valters IT"
        date = "2026-01-15"
        reference = "CVE-2026-2401"
    strings:
        $sensitive1 = /password\s*=\s*["']?[^"'\s]+["']?/ nocase
        $sensitive2 = /api[_-]?key\s*=\s*["']?[^"'\s]+["']?/ nocase
        $sensitive3 = /secret\s*=\s*["']?[^"'\s]+["']?/ nocase
        $log_pattern = /ERROR|WARN|DEBUG|INFO/
    condition:
        any of ($sensitive*) and $log_pattern
}

Sigma Rule

title: CVE-2026-2401 - Sensitive Data in Log Files
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects log entries containing sensitive data (passwords, API keys) which may indicate exploitation of CVE-2026-2401.
author: Valters IT
date: 2026-01-15
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-2401
logsource:
    category: application
    product: schneider_electric
detection:
    selection:
        - EventID: 1  # Example: Windows Event ID for process creation
        - Data: "*password=*"
        - Data: "*api_key=*"
        - Data: "*secret=*"
    condition: selection
falsepositives:
    - Legitimate logging of configuration changes
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2026-2401 - Potential Sensitive Data Exfiltration via Logs"; flow:to_server,established; content:"password"; nocase; content:"api_key"; nocase; content:"secret"; nocase; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

1. Apply Vendor Patch: Immediately apply the patch provided by Schneider Electric. Contact Schneider Electric support for the specific patch details.
2. Log Sanitization: Implement log sanitization to mask or remove sensitive data (e.g., passwords, API keys) before writing to log files.
3. Access Control: Restrict access to log files to only authorized personnel. Use file system permissions and audit logging.
4. User Training: Train Web Admin users to recognize and avoid executing files from untrusted sources.
5. Monitoring: Implement real-time monitoring of log files for sensitive data exposure. Use the detection rules provided above.
6. Incident Response: If exploitation is suspected, immediately isolate the affected system, review logs for exposed data, and rotate any compromised credentials.

Valters IT

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