CVE-2020-29015: Fortinet FortiWeb SQLi Vulnerability

CVE-2020-29015 Overview

A blind SQL injection vulnerability exists in the user interface of FortiWeb, Fortinet's web application firewall (WAF) solution. This vulnerability allows an unauthenticated, remote attacker to execute arbitrary SQL queries or commands by sending a request with a crafted Authorization header containing a malicious SQL statement. The vulnerability affects FortiWeb versions 6.3.0 through 6.3.7 and versions before 6.2.4.

Critical Impact

Unauthenticated attackers can execute arbitrary SQL queries remotely via malicious Authorization headers, potentially compromising sensitive data, modifying database contents, or gaining unauthorized access to the underlying system.

Affected Products

• Fortinet FortiWeb 6.3.0 through 6.3.7
• Fortinet FortiWeb versions before 6.2.4

Discovery Timeline

• 2021-01-14 - CVE CVE-2020-29015 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-29015

Vulnerability Analysis

This vulnerability is classified as CWE-89 (SQL Injection), specifically a blind SQL injection variant. The flaw resides in how FortiWeb's user interface processes the Authorization header in HTTP requests. The lack of proper input validation and sanitization allows attackers to inject malicious SQL statements through this authentication mechanism.

Blind SQL injection attacks are particularly dangerous because they allow attackers to extract data even when the application does not directly display database output. Attackers can infer information through time-based or boolean-based techniques, systematically extracting sensitive information from the underlying database without visible error messages.

The network-accessible nature of this vulnerability, combined with the fact that no authentication is required to exploit it, makes this flaw especially severe. FortiWeb devices are typically positioned at the network perimeter protecting web applications, making them high-value targets for attackers seeking to compromise security infrastructure.

Root Cause

The root cause of this vulnerability is improper input validation and insufficient sanitization of user-supplied data within the Authorization header processing logic. The FortiWeb user interface fails to properly escape or parameterize SQL queries constructed from the Authorization header values, allowing specially crafted input to modify the intended SQL query structure.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can remotely send crafted HTTP requests to the FortiWeb management interface with a malicious Authorization header. The injected SQL statement is processed by the backend database, allowing the attacker to execute arbitrary SQL commands.

The exploitation mechanism involves crafting an Authorization header that contains SQL syntax designed to manipulate the database query execution. Since this is a blind SQL injection, the attacker typically uses time-based delays or conditional responses to infer the results of their queries, gradually extracting database contents or modifying data.

Detection Methods for CVE-2020-29015

Indicators of Compromise

• Unusual or malformed Authorization headers in HTTP request logs containing SQL keywords (SELECT, UNION, INSERT, DELETE, DROP, etc.)
• Abnormal response times from the FortiWeb management interface that may indicate time-based SQL injection attempts
• Unexpected database queries or errors in FortiWeb backend logs
• Authentication bypass attempts or unauthorized access to management functions

Detection Strategies

• Implement web application firewall rules to detect SQL injection patterns in Authorization headers
• Monitor HTTP access logs for requests containing SQL metacharacters and keywords in authentication-related headers
• Deploy intrusion detection signatures specifically targeting SQL injection attempts against FortiWeb devices
• Enable verbose logging on FortiWeb devices to capture detailed request information for forensic analysis

Monitoring Recommendations

• Establish baseline behavior for FortiWeb management interface access and alert on anomalies
• Monitor network traffic to FortiWeb management ports for suspicious patterns
• Implement log aggregation and correlation to detect distributed attack attempts
• Set up alerts for repeated authentication failures or unusual query patterns in database logs

How to Mitigate CVE-2020-29015

Immediate Actions Required

• Upgrade FortiWeb to version 6.3.8 or later, or version 6.2.4 or later immediately
• Restrict network access to FortiWeb management interfaces to trusted IP addresses only
• Implement additional network segmentation to protect FortiWeb management access
• Review access logs for any signs of exploitation attempts prior to patching

Patch Information

Fortinet has released security updates to address this vulnerability. Organizations should upgrade to FortiWeb 6.3.8 or later for the 6.3.x branch, or 6.2.4 or later for the 6.2.x branch. Detailed patch information and upgrade instructions are available in the FortiGuard Security Advisory FG-IR-20-124.

Workarounds

• Restrict access to the FortiWeb management interface to trusted internal networks only using firewall rules or access control lists
• Implement strong network segmentation to isolate management interfaces from untrusted networks
• Consider placing FortiWeb management interfaces behind a VPN to require authenticated access before reaching the management portal
• Enable additional logging and monitoring on all FortiWeb devices while awaiting patch deployment

# Example: Restrict FortiWeb management access using firewall rules
# Allow management access only from trusted administrator network
iptables -A INPUT -p tcp --dport 443 -s 10.0.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP

# Enable detailed logging for management interface access
# (Consult FortiWeb documentation for device-specific logging configuration)