CVE-2025-69770: MojoPortal CMS Zip Slip RCE Vulnerability

CVE-2025-69770 Overview

A critical zip slip vulnerability exists in the /DesignTools/SkinList.aspx endpoint of MojoPortal CMS v2.9.0.1. This path traversal flaw allows attackers to execute arbitrary commands by uploading a specially crafted zip file containing malicious path sequences. When the application extracts the archive, it fails to properly validate file paths within the zip, enabling attackers to write files to arbitrary locations on the server filesystem.

Critical Impact

This vulnerability enables remote command execution through malicious zip file uploads, potentially allowing complete server compromise without authentication.

Affected Products

• MojoPortal CMS v2.9.0.1
• MojoPortal CMS versions prior to v2.9.1

Discovery Timeline

• 2026-02-13 - CVE CVE-2025-69770 published to NVD
• 2026-02-13 - Last updated in NVD database

Technical Details for CVE-2025-69770

Vulnerability Analysis

The zip slip vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory) occurs in the skin upload functionality of MojoPortal CMS. The /DesignTools/SkinList.aspx endpoint accepts zip file uploads to install custom themes or skins, but fails to properly sanitize the file paths contained within the archive during extraction.

When a zip archive is uploaded, the application extracts its contents without validating whether the archived file paths contain directory traversal sequences such as ../. An attacker can craft a malicious zip file where entries reference paths outside the intended extraction directory, such as ../../../webroot/shell.aspx. Upon extraction, these files are written to arbitrary locations on the server, bypassing the intended upload directory restrictions.

This type of vulnerability is particularly dangerous in web applications because an attacker can write executable files (such as .aspx web shells) to the webroot, gaining the ability to execute arbitrary commands on the server with the privileges of the web application process.

Root Cause

The root cause is insufficient path validation during zip archive extraction. The application directly uses file paths from the zip archive entries without canonicalizing the paths or checking for directory traversal sequences. The extraction routine does not verify that the final resolved path remains within the designated extraction directory, allowing path components like .. to escape the intended directory boundary.

Attack Vector

The attack is network-based and can be executed by any user with access to the SkinList endpoint. An attacker crafts a zip archive containing files with malicious path entries (e.g., ../../wwwroot/malicious.aspx). When this archive is uploaded through the /DesignTools/SkinList.aspx endpoint, the extraction process writes the malicious file to an attacker-controlled location. The attacker can then access the uploaded web shell or executable to gain remote command execution on the server.

The vulnerability mechanism involves:

1. Attacker creates a zip archive with entries containing path traversal sequences
2. Attacker uploads the malicious zip file to the SkinList endpoint
3. Server extracts archive contents without sanitizing file paths
4. Malicious files are written outside the intended extraction directory
5. Attacker accesses the uploaded payload to execute arbitrary commands

For technical details on the exploitation method, see the GitHub Zipslip Vulnerability Report.

Detection Methods for CVE-2025-69770

Indicators of Compromise

• Unexpected .aspx, .ashx, or executable files appearing in the webroot or other sensitive directories
• Web server logs showing requests to the /DesignTools/SkinList.aspx endpoint with zip file uploads followed by requests to newly created suspicious files
• File system activity showing file creation events outside the designated skin upload directory
• Presence of web shells or backdoor files in application directories

Detection Strategies

• Monitor file upload events to the /DesignTools/SkinList.aspx endpoint and analyze uploaded zip file contents for path traversal sequences
• Implement file integrity monitoring (FIM) on critical application directories to detect unauthorized file creation
• Deploy web application firewall (WAF) rules to inspect zip file uploads for malicious path patterns
• Configure endpoint detection to alert on suspicious file creation events by the IIS worker process

Monitoring Recommendations

• Enable detailed logging for the MojoPortal application and web server to capture all file upload activity
• Implement real-time monitoring for new file creation events in web-accessible directories
• Configure alerts for outbound connections from the web server that may indicate post-exploitation activity
• Review access logs for the /DesignTools/ path regularly to identify unauthorized access attempts

How to Mitigate CVE-2025-69770

Immediate Actions Required

• Upgrade MojoPortal CMS to version 2.9.1 or later immediately
• Restrict access to the /DesignTools/ directory to authenticated administrators only
• Implement network-level access controls to limit who can reach administrative endpoints
• Audit the server filesystem for any unauthorized files that may have been uploaded through exploitation

Patch Information

MojoPortal has addressed this vulnerability in version 2.9.1. Organizations running MojoPortal CMS should upgrade to the patched version as soon as possible. For detailed release information, see the MojoPortal 2.9.1 Release Notes. Additional security information is available at the GitHub MojoPortal Security page.

Workarounds

• If immediate patching is not possible, disable or restrict access to the /DesignTools/SkinList.aspx endpoint through web server configuration
• Implement strict authentication requirements for all administrative endpoints
• Deploy a web application firewall with rules to block zip file uploads containing path traversal patterns
• Consider temporarily taking the affected endpoint offline until the patch can be applied

# IIS URL Rewrite rule to block access to vulnerable endpoint
# Add to web.config in MojoPortal root directory
# <system.webServer>
#   <rewrite>
#     <rules>
#       <rule name="Block SkinList" stopProcessing="true">
#         <match url="DesignTools/SkinList.aspx" />
#         <action type="CustomResponse" statusCode="403" />
#       </rule>
#     </rules>
#   </rewrite>
# </system.webServer>