CVE-2021-22003: VMware Identity Manager Auth Bypass Flaw

CVE-2021-22003 Overview

VMware Workspace ONE Access and Identity Manager contain an unintended login interface exposure vulnerability. These products unintentionally provide a login interface on port 7443, creating an attack surface that should not be accessible. A malicious actor with network access to port 7443 may attempt user enumeration or brute force attacks against the login endpoint. The practical exploitation of this vulnerability depends on the target environment's lockout policy configuration and password complexity requirements for the targeted accounts.

Critical Impact

Network-accessible login interface on port 7443 enables user enumeration and brute force attacks against VMware identity management infrastructure, potentially compromising enterprise authentication systems.

Affected Products

• VMware Identity Manager versions 3.3.2, 3.3.3, 3.3.4, 3.3.5
• VMware Workspace ONE Access versions 20.01, 20.10, 20.10.01
• VMware Cloud Foundation versions 4.0, 4.0.1, 4.1, 4.1.0.1, 4.2.1
• VMware vRealize Suite Lifecycle Manager versions 8.0, 8.0.1, 8.1, 8.2
• Linux Kernel (as underlying platform)

Discovery Timeline

• August 31, 2021 - CVE-2021-22003 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2021-22003

Vulnerability Analysis

This vulnerability stems from an improper restriction of excessive authentication attempts (CWE-307). The VMware Workspace ONE Access and Identity Manager products inadvertently expose a login interface on port 7443 that was not intended to be publicly accessible. This exposed interface lacks adequate protections against automated authentication attacks, allowing attackers to systematically attempt credential guessing or enumerate valid usernames based on application responses.

The exposed login endpoint on port 7443 operates independently from the primary authentication interface, potentially bypassing security controls implemented on the standard ports. This architectural oversight means that even environments with robust security configurations on their primary authentication endpoints may remain vulnerable through this alternate pathway.

Root Cause

The root cause of this vulnerability is an improper restriction of excessive authentication attempts combined with an unintended service exposure. The login interface on port 7443 was not designed to be externally accessible, yet it remains reachable to any network-connected attacker. This interface may not implement the same rate limiting, account lockout policies, or monitoring controls as the primary authentication endpoints, creating a weakness that can be exploited for credential attacks.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker with network access to port 7443 on a vulnerable VMware Workspace ONE Access or Identity Manager instance can exploit this vulnerability through the following approach:

The attacker first identifies an accessible VMware identity management appliance with port 7443 open. Using automated tools, they can then perform user enumeration by analyzing response differences when submitting valid versus invalid usernames. Once valid usernames are identified, brute force attacks can be launched against those accounts. The success of the brute force component depends on the target's password policy complexity and any lockout mechanisms that may be in place on the underlying directory services.

Detection Methods for CVE-2021-22003

Indicators of Compromise

• Unusual authentication traffic volume targeting port 7443 on VMware identity management appliances
• Multiple failed login attempts from single or distributed source IP addresses against port 7443
• Authentication logs showing systematic enumeration patterns with sequential or common usernames
• Network connections to port 7443 from external or unexpected IP ranges

Detection Strategies

• Deploy network monitoring rules to alert on connections to port 7443 on VMware Workspace ONE Access and Identity Manager systems
• Implement authentication log correlation to detect brute force patterns across both standard and port 7443 endpoints
• Configure IDS/IPS signatures to identify automated authentication attack tools targeting VMware products
• Monitor for unusual volumes of HTTP requests to the login endpoint on port 7443

Monitoring Recommendations

• Enable detailed authentication logging on VMware Workspace ONE Access and Identity Manager appliances
• Implement SIEM rules to correlate failed authentication events across all VMware identity infrastructure
• Configure network flow monitoring to track connections to port 7443 for anomaly detection
• Set up alerting thresholds for failed login attempts that may indicate enumeration or brute force activity

How to Mitigate CVE-2021-22003

Immediate Actions Required

• Apply the security patches referenced in VMware Security Advisory VMSA-2021-0016
• Restrict network access to port 7443 using firewall rules to only allow authorized administrative IP addresses
• Review and strengthen account lockout policies to limit brute force effectiveness
• Audit authentication logs for any signs of previous exploitation attempts

Patch Information

VMware has addressed this vulnerability in security advisory VMSA-2021-0016. Administrators should consult the VMware Security Advisory VMSA-2021-0016 for specific patched versions and upgrade instructions for their deployed products. Apply the appropriate patches for VMware Identity Manager, Workspace ONE Access, Cloud Foundation, and vRealize Suite Lifecycle Manager based on your current version.

Workarounds

• Implement network-level access controls to block external access to port 7443 on all VMware identity management appliances
• Configure host-based firewalls on the appliances to deny connections to port 7443 from untrusted networks
• Deploy a web application firewall (WAF) to rate-limit and monitor authentication requests to the exposed endpoint
• Strengthen password policies and ensure robust account lockout mechanisms are enforced at the directory service level

# Example firewall rule to restrict access to port 7443
# Allow only specific administrative subnets
iptables -A INPUT -p tcp --dport 7443 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 7443 -j DROP

# Verify the rules are applied
iptables -L -n | grep 7443