CVE-2025-3709: Flowring Agentflow Auth Bypass Vulnerability

CVE-2025-3709 Overview

Agentflow from Flowring Technology contains an Account Lockout Bypass vulnerability that allows unauthenticated remote attackers to perform password brute force attacks against the application. This authentication bypass flaw (CWE-307: Improper Restriction of Excessive Authentication Attempts) enables attackers to circumvent security mechanisms designed to prevent automated credential guessing attacks.

Critical Impact

Unauthenticated remote attackers can bypass account lockout protections to conduct unlimited password brute force attacks, potentially leading to complete account compromise with high confidentiality, integrity, and availability impact.

Affected Products

• Flowring Agentflow 4.0

Discovery Timeline

• 2025-05-02 - CVE-2025-3709 published to NVD
• 2025-05-07 - Last updated in NVD database

Technical Details for CVE-2025-3709

Vulnerability Analysis

This vulnerability stems from improper implementation of account lockout mechanisms in Flowring Agentflow. The application fails to properly restrict excessive authentication attempts, allowing attackers to bypass protections that should prevent brute force attacks. When exploited, an attacker can attempt an unlimited number of password combinations against user accounts without triggering lockout mechanisms.

The vulnerability is particularly severe because it requires no authentication or user interaction to exploit. Attackers can launch automated attacks from the network against any user account, systematically guessing passwords until they gain unauthorized access.

Root Cause

The root cause is classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts). The Agentflow application does not adequately track or limit failed authentication attempts, or the lockout mechanism can be circumvented through specific request manipulation. This allows attackers to perform high-volume credential guessing attacks that would normally be blocked by account lockout policies.

Attack Vector

The attack vector is network-based, enabling remote exploitation without requiring any privileges or user interaction. An attacker can target the Agentflow authentication endpoint and systematically attempt password combinations against known or enumerated usernames. The bypass of the lockout mechanism removes the primary defense against such brute force attacks.

The attack process involves identifying the authentication endpoint, crafting requests that evade the lockout tracking mechanism, and automating password guessing attempts at high volume until valid credentials are discovered.

Detection Methods for CVE-2025-3709

Indicators of Compromise

• High volume of authentication requests from single IP addresses or IP ranges targeting Agentflow
• Multiple failed login attempts for the same user account that do not trigger lockout
• Authentication attempts occurring at unusually high rates (e.g., multiple attempts per second)
• Successful login following numerous failed attempts without observed lockout period

Detection Strategies

• Monitor authentication logs for anomalous patterns of failed login attempts that exceed normal lockout thresholds
• Implement network-level monitoring to detect brute force attack patterns against Agentflow services
• Configure alerts for authentication attempts from suspicious sources or at unusual times
• Deploy web application firewall (WAF) rules to detect and block automated credential stuffing attempts

Monitoring Recommendations

• Enable detailed logging for all authentication events in Agentflow
• Establish baseline metrics for normal authentication patterns and alert on deviations
• Monitor for sequential or distributed login attempts that may indicate coordinated attacks
• Review authentication logs regularly for signs of bypass attempts or successful unauthorized access

How to Mitigate CVE-2025-3709

Immediate Actions Required

• Check with Flowring Technology for available security patches addressing this vulnerability
• Implement network-level rate limiting on authentication endpoints
• Deploy additional authentication controls such as CAPTCHA or multi-factor authentication
• Restrict access to Agentflow authentication services to trusted networks where possible
• Monitor for exploitation attempts while awaiting vendor patch

Patch Information

Organizations should consult the TWCERT Security Alert and TWCERT Incident Report for the latest patch information and vendor advisories from Flowring Technology. Apply vendor-provided security updates as soon as they become available.

Workarounds

• Implement IP-based rate limiting at the network or web application firewall level to restrict authentication attempts
• Deploy CAPTCHA or similar challenge-response mechanisms on login pages to prevent automated attacks
• Enable multi-factor authentication (MFA) to add an additional layer of protection beyond passwords
• Consider placing Agentflow behind a VPN or restricting access to trusted IP ranges
• Implement application-level monitoring to detect and block brute force attempts in real-time

# Example: Network-level rate limiting using iptables (adapt to your environment)
# Limit new connections to authentication endpoint to 10 per minute per IP
iptables -A INPUT -p tcp --dport 443 -m state --state NEW -m recent --set
iptables -A INPUT -p tcp --dport 443 -m state --state NEW -m recent --update --seconds 60 --hitcount 10 -j DROP