CVE-2025-47855: Fortinet FortiFone Information Disclosure

CVE-2025-47855 Overview

CVE-2025-47855 is a critical information disclosure vulnerability (CWE-200) affecting Fortinet FortiFone devices. The vulnerability allows an unauthenticated attacker to obtain sensitive device configuration data via specially crafted HTTP or HTTPS requests. This exposure of sensitive information to unauthorized actors poses significant security risks, as device configurations often contain credentials, network topology details, and other sensitive operational parameters.

Critical Impact

Unauthenticated attackers can remotely extract complete device configurations from vulnerable FortiFone systems, potentially exposing credentials, network settings, and sensitive operational data without any authentication required.

Affected Products

• Fortinet FortiFone 7.0.0 through 7.0.1
• Fortinet FortiFone 3.0.13 through 3.0.23

Discovery Timeline

• 2026-01-13 - CVE CVE-2025-47855 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2025-47855

Vulnerability Analysis

This vulnerability represents a significant security weakness in the Fortinet FortiFone web interface. The flaw allows unauthenticated remote attackers to access device configuration files through specially crafted HTTP or HTTPS requests. The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), indicating that the application fails to properly restrict access to sensitive configuration data.

The attack can be executed remotely over the network without requiring any user interaction or prior authentication. Once exploited, attackers gain access to complete device configurations which may include administrative credentials, VoIP settings, network configurations, and other sensitive operational parameters. This level of access could facilitate further attacks including credential theft, network reconnaissance, or complete device compromise.

Root Cause

The root cause of this vulnerability lies in improper access control mechanisms within the FortiFone web service. The device fails to adequately verify authentication status before serving sensitive configuration data to requesters. This allows attackers to craft specific HTTP or HTTPS requests that bypass authentication checks and directly retrieve configuration files that should only be accessible to authenticated administrators.

Attack Vector

The attack vector is network-based, requiring the attacker to have network connectivity to the vulnerable FortiFone device's web interface. The attacker sends specially crafted HTTP or HTTPS requests to the device, which improperly processes these requests and returns configuration data without verifying the requester's authentication status.

The exploitation process involves:

1. Identifying a vulnerable FortiFone device accessible over the network
2. Crafting malicious HTTP/HTTPS requests targeting configuration endpoints
3. Receiving sensitive device configuration data in the response
4. Extracting credentials and sensitive information from the configuration dump

Detection Methods for CVE-2025-47855

Indicators of Compromise

• Unusual HTTP/HTTPS requests to FortiFone web interfaces from unauthorized IP addresses
• Unexpected access patterns targeting configuration-related endpoints
• Authentication logs showing configuration access without prior successful login events
• Network traffic analysis revealing configuration data being transmitted to external destinations

Detection Strategies

• Monitor web server logs on FortiFone devices for anomalous request patterns targeting configuration endpoints
• Implement network intrusion detection rules to identify attempts to access configuration data without authentication
• Deploy SentinelOne agents to monitor endpoint behavior and detect suspicious network communications with FortiFone devices
• Review access logs for requests to sensitive configuration endpoints from non-administrative IP ranges

Monitoring Recommendations

• Enable comprehensive logging on all FortiFone devices to capture HTTP/HTTPS request details
• Configure SIEM solutions to alert on configuration file access attempts from unauthenticated sources
• Implement network segmentation to restrict direct access to FortiFone management interfaces
• Conduct periodic log reviews to identify potential exploitation attempts

How to Mitigate CVE-2025-47855

Immediate Actions Required

• Apply the security patches provided by Fortinet as soon as they become available
• Restrict network access to FortiFone management interfaces using firewall rules
• Implement network segmentation to isolate FortiFone devices from untrusted networks
• Audit existing device configurations for potential credential exposure and rotate any exposed credentials

Patch Information

Fortinet has acknowledged this vulnerability and issued a security advisory. Administrators should refer to the Fortinet Security Advisory FG-IR-25-260 for official patch information and remediation guidance. Apply the latest firmware updates for FortiFone 7.0.x and 3.0.x branches as directed by Fortinet.

Workarounds

• Restrict access to FortiFone web management interfaces to trusted administrative networks only
• Implement firewall rules to block external access to HTTP/HTTPS management ports on FortiFone devices
• Use VPN connections for remote administration instead of exposing management interfaces directly to the network
• Monitor and log all access attempts to FortiFone management interfaces pending patch deployment

# Example firewall rule to restrict FortiFone management access
# Adjust IP ranges and interface names according to your environment

# Allow access only from trusted admin network
iptables -A INPUT -p tcp --dport 443 -s 10.0.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -s 10.0.1.0/24 -j ACCEPT

# Block all other access to management ports
iptables -A INPUT -p tcp --dport 443 -j DROP
iptables -A INPUT -p tcp --dport 80 -j DROP