CVE-2025-62003 is a time-of-check to time-of-use (TOCTOU) race condition vulnerability classified under CWE-367, affecting BullWall Server Intrusion Protection versions 4.6.0.0, 4.6.0.6, 4.6.0.7, and 4.6.1.4. The vulnerability manifests as a noticeable delay between the initial connection and the enforcement of multi-factor authentication (MFA) when users connect via Remote Desktop Protocol (RDP). During this delay, a remote attacker who is already authenticated with administrative privileges can exploit the timing gap to perform actions that bypass the intrusion detection mechanisms of BullWall. This race condition allows the attacker to evade detection and potentially execute unauthorized commands or access sensitive data before the MFA check completes. The vulnerability requires the attacker to have administrative privileges on the target system, which limits the initial attack surface but increases the severity due to the elevated access level. The CVSS 3.1 base score is 6.2, reflecting medium severity, with attack vector network, high attack complexity, required privileges high, no user interaction, unchanged scope, and high impact on confidentiality and integrity, with low impact on availability. No public patches or exploits are currently known, but the affected versions are widely used in enterprise environments for server protection. The vulnerability highlights a design flaw in the authentication workflow of BullWall’s product, where the timing window before MFA enforcement creates a security gap. Organizations relying on BullWall Server Intrusion Protection should be aware of this issue and monitor for updates or patches from the vendor.

For European organizations, this vulnerability poses a significant risk especially in environments where BullWall Server Intrusion Protection is deployed to secure RDP access to critical servers. The ability for an attacker with administrative privileges to bypass detection during the MFA delay window undermines the effectiveness of the security controls, potentially allowing stealthy lateral movement, data exfiltration, or persistence mechanisms without triggering alerts. Confidentiality and integrity of sensitive data and systems are at risk, particularly in sectors such as finance, healthcare, government, and critical infrastructure where RDP is commonly used for remote administration. The medium severity rating reflects that while exploitation requires prior administrative access, the bypass of detection can facilitate further attacks and complicate incident response. The lack of known exploits in the wild provides a window for mitigation, but organizations should not delay in addressing the vulnerability. Failure to mitigate could lead to increased risk of advanced persistent threats (APTs) leveraging this timing gap to evade detection. Additionally, the vulnerability could impact compliance with European data protection regulations if it leads to unauthorized data access or breaches.

1. Immediately restrict RDP access to trusted administrators using network-level controls such as VPNs, IP whitelisting, or jump servers to reduce exposure. 2. Implement compensating controls such as enhanced logging and real-time monitoring of RDP sessions to detect suspicious activity during the MFA delay window. 3. Where possible, reduce or eliminate the delay before MFA enforcement by configuring BullWall or the underlying authentication system to enforce MFA as early as possible in the connection process. 4. Apply strict session timeout and automatic lockout policies to limit the window of opportunity for exploitation. 5. Conduct regular audits of administrative accounts and their usage to detect unauthorized privilege escalations. 6. Engage with BullWall support to obtain any available patches or workarounds and monitor for vendor advisories. 7. Consider deploying additional endpoint detection and response (EDR) solutions to identify anomalous behavior that may bypass BullWall detection. 8. Educate administrators on the risks of this vulnerability and enforce strong credential hygiene and MFA usage beyond BullWall’s controls. 9. Test incident response procedures to ensure rapid detection and containment if exploitation is suspected. 10. Plan for timely patching once a fix is released to close the vulnerability definitively.