CVE-2024-39717: Versa Director Auth Bypass Vulnerability

CVE-2024-39717 Overview

CVE-2024-39717 is a dangerous file type upload vulnerability affecting Versa Director, a critical network management platform used for SD-WAN orchestration. The vulnerability exists in the GUI's "Change Favicon" customization feature, which can be abused by authenticated administrative users to upload malicious files disguised with a .png extension. This flaw allows attackers with Provider-Data-Center-Admin or Provider-Data-Center-System-Admin privileges to upload arbitrary files masquerading as image files, potentially leading to remote code execution on affected systems.

Critical Impact

This vulnerability is actively exploited in the wild and has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog. Organizations using affected Versa Director versions should prioritize patching immediately.

Affected Products

• Versa Networks Versa Director version 21.2.2
• Versa Networks Versa Director version 21.2.3
• Versa Networks Versa Director version 22.1.1
• Versa Networks Versa Director version 22.1.2
• Versa Networks Versa Director version 22.1.3

Discovery Timeline

• 2024-08-22 - CVE-2024-39717 published to NVD
• 2025-10-30 - Last updated in NVD database

Technical Details for CVE-2024-39717

Vulnerability Analysis

The vulnerability stems from improper validation of file types in the Versa Director GUI's favicon customization feature. The application fails to properly verify that uploaded files are legitimate image files, instead relying solely on file extension validation. This insufficient validation allows attackers to upload malicious executable content disguised with a .png extension.

The attack requires prior authentication with elevated administrative privileges (Provider-Data-Center-Admin or Provider-Data-Center-System-Admin), limiting the attack surface to scenarios involving compromised administrative credentials or insider threats. However, once exploited, the vulnerability can result in complete system compromise with high impact on confidentiality, integrity, and availability.

This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type), a common web application security weakness where applications fail to properly restrict file uploads based on actual content rather than superficial attributes like file extensions.

Root Cause

The root cause of CVE-2024-39717 is the lack of proper content-type validation in the favicon upload functionality. The application accepts files based on their extension (.png) without verifying the actual file content or MIME type. This allows attackers to embed malicious payloads—such as web shells, scripts, or executable code—within files that pass extension-based checks.

The vulnerability exists because:

• The file upload handler only validates the file extension, not the file content
• No server-side validation checks the actual MIME type or file signature (magic bytes)
• Uploaded files may be stored in locations accessible for execution by the web server

Attack Vector

The attack is network-based and requires the attacker to have valid administrative credentials for the Versa Director platform. The exploitation flow involves:

1. An attacker obtains or compromises Provider-Data-Center-Admin or Provider-Data-Center-System-Admin credentials
2. The attacker authenticates to the Versa Director GUI
3. The attacker navigates to the favicon customization feature
4. A malicious file (such as a web shell or reverse shell payload) is renamed with a .png extension
5. The attacker uploads the malicious file through the "Change Favicon" option
6. If the uploaded file is stored in an executable location, the attacker can trigger code execution

The vulnerability requires no user interaction beyond the initial authentication and can be exploited over the network. Given that Versa Director is often deployed to manage critical SD-WAN infrastructure, successful exploitation could provide attackers with a foothold to pivot into enterprise networks and downstream managed devices.

Detection Methods for CVE-2024-39717

Indicators of Compromise

• Suspicious file uploads with .png extension that contain non-image content in the favicon upload directory
• Web server logs showing requests to favicon-related endpoints from unusual IP addresses or with anomalous parameters
• Presence of unexpected files in Versa Director upload directories that fail image validation checks
• Authentication logs showing successful administrative logins followed by favicon modification activities from unfamiliar sources

Detection Strategies

• Implement file integrity monitoring (FIM) on Versa Director upload directories to detect unauthorized file modifications
• Deploy web application firewall (WAF) rules to inspect file uploads and block content mismatched with declared file types
• Enable detailed audit logging for all administrative actions in Versa Director, particularly customization and upload operations
• Configure SIEM correlation rules to alert on administrative authentication followed by file upload activities outside normal business hours

Monitoring Recommendations

• Monitor Versa Director authentication logs for brute force attempts or credential stuffing targeting administrative accounts
• Implement anomaly detection for administrative user behavior, flagging unusual access patterns or configuration changes
• Establish baseline network traffic patterns for Versa Director and alert on deviations that could indicate command-and-control communications
• Review and audit Provider-Data-Center-Admin account usage regularly to identify potentially compromised credentials

How to Mitigate CVE-2024-39717

Immediate Actions Required

• Apply the latest security patches from Versa Networks immediately, as this vulnerability is actively exploited
• Review all administrative accounts and rotate credentials for Provider-Data-Center-Admin and Provider-Data-Center-System-Admin roles
• Conduct forensic analysis of Versa Director systems to identify any indicators of prior exploitation
• Restrict network access to the Versa Director management interface to authorized administrative networks only

Patch Information

Versa Networks has released security updates to address this vulnerability. Organizations should consult the Versa Networks Security Bulletin for specific patch versions and upgrade instructions. Given the active exploitation of this vulnerability and its inclusion in the CISA Known Exploited Vulnerabilities Catalog, federal agencies and critical infrastructure operators are mandated to apply patches within specified deadlines.

Workarounds

• Implement strict network segmentation to limit access to the Versa Director management interface from untrusted networks
• Enable multi-factor authentication (MFA) for all administrative accounts to reduce the risk of credential compromise
• Disable or restrict access to the favicon customization feature if not operationally required until patches can be applied
• Deploy endpoint detection and response (EDR) solutions on Versa Director hosts to detect and block malicious post-exploitation activities

# Example: Restrict management interface access via iptables
# Allow management access only from trusted admin network
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP