CVE-2025-15577: Valmet DNA Web Tools Path Traversal

CVE-2025-15577 Overview

CVE-2025-15577 is a path traversal vulnerability (CWE-22) affecting Valmet DNA Web Tools. An unauthenticated attacker can exploit this vulnerability by manipulating URLs to achieve arbitrary file read access on vulnerable systems. This vulnerability requires no user interaction or prior authentication, making it particularly dangerous for exposed deployments.

Critical Impact

Unauthenticated attackers can read arbitrary files from affected systems, potentially exposing sensitive configuration data, credentials, and proprietary information.

Affected Products

• Valmet DNA Web Tools C2022
• Valmet DNA Web Tools versions older than C2022

Discovery Timeline

• 2026-02-12 - CVE CVE-2025-15577 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2025-15577

Vulnerability Analysis

This path traversal vulnerability allows unauthenticated remote attackers to read arbitrary files from the target system by manipulating URL parameters. The attack is network-accessible, requires no special privileges or user interaction, and has a low attack complexity. Successful exploitation could result in high confidentiality impact on both the vulnerable system and subsequent systems, enabling attackers to access sensitive files such as configuration files, credentials, and proprietary operational data from Valmet DNA industrial control systems.

Root Cause

The vulnerability stems from improper input validation (CWE-22: Improper Limitation of a Pathname to a Restricted Directory) in the Valmet DNA Web Tools application. The application fails to properly sanitize user-supplied input in URL parameters before using them to construct file paths, allowing attackers to use directory traversal sequences (such as ../) to escape the intended directory and access files elsewhere on the file system.

Attack Vector

The attack is conducted over the network by manipulating URL parameters sent to the Valmet DNA Web Tools application. An attacker can craft malicious requests containing path traversal sequences to navigate outside the web root directory and access sensitive files on the server. Since no authentication is required, any attacker with network access to the vulnerable application can attempt exploitation.

The vulnerability allows an attacker to construct URLs with directory traversal sequences (e.g., ../../../etc/passwd or similar patterns) to read files outside the intended web directory. The attacker sends a crafted HTTP request to the vulnerable endpoint, and the server returns the contents of the requested file if it exists and is readable by the web application process. For detailed technical information, refer to the Valmet Security Advisory.

Detection Methods for CVE-2025-15577

Indicators of Compromise

• HTTP requests containing path traversal sequences such as ../, ..%2f, ..%5c, or URL-encoded variants targeting the Valmet DNA Web Tools application
• Unusual access patterns to sensitive system files such as /etc/passwd, configuration files, or application credentials
• Web server logs showing repeated requests with directory traversal patterns from single or multiple source IPs

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing path traversal sequences
• Monitor web server access logs for patterns indicative of directory traversal attempts
• Deploy network intrusion detection systems (IDS) with signatures for path traversal attacks
• Configure application-level logging to capture and alert on requests to files outside the web root

Monitoring Recommendations

• Enable detailed logging on Valmet DNA Web Tools and forward logs to a SIEM for centralized analysis
• Set up alerts for access attempts to sensitive file paths from web application processes
• Monitor for anomalous outbound data transfers that could indicate successful file exfiltration

How to Mitigate CVE-2025-15577

Immediate Actions Required

• Review network architecture to ensure Valmet DNA Web Tools is not directly exposed to untrusted networks
• Implement network segmentation to restrict access to the vulnerable application to authorized personnel only
• Apply vendor-provided patches or updates as soon as they become available
• Deploy a web application firewall (WAF) with path traversal attack signatures as an interim protective measure

Patch Information

Valmet has published a security advisory for this vulnerability. Organizations should consult the Valmet Security Advisory for CVE-2025-15577 for official patch information, updated software versions, and remediation guidance. Upgrade Valmet DNA Web Tools to a version newer than C2022 once a patched version is available.

Workarounds

• Restrict network access to Valmet DNA Web Tools using firewall rules or access control lists (ACLs) to allow only trusted IP addresses
• Place the application behind a reverse proxy or WAF configured to filter malicious path traversal patterns
• Disable or limit functionality of the web tools interface if not operationally critical until a patch can be applied

# Example: Restrict access to Valmet DNA Web Tools using iptables
# Allow access only from trusted management network (example: 10.0.1.0/24)
iptables -A INPUT -p tcp --dport 443 -s 10.0.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP