CVE-2023-37596 in PBX
Summary
by MITRE • 07/11/2023
Cross Site Request Forgery (CSRF) vulnerability in issabel-pbx v.4.0.0-6 allows a remote attacker to cause a denial of service via a crafted script to the deleteuser function.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/18/2026
The CVE-2023-37596 vulnerability represents a critical cross site request forgery flaw within the issabel-pbx version 4.0.0-6 telephony system. This vulnerability exists in the deleteuser function which lacks proper authentication and validation mechanisms, allowing remote attackers to manipulate the system through crafted malicious requests. The issue stems from the absence of anti-CSRF tokens or other protective measures that would normally validate the legitimacy of user requests. The vulnerability enables attackers to execute unauthorized deletion operations against user accounts, potentially leading to complete service disruption. This flaw resides in the web interface of the PBX system, making it accessible over network connections without requiring authentication credentials. The attack vector is particularly dangerous as it can be exploited through social engineering techniques where users are tricked into visiting malicious websites or clicking on compromised links that automatically submit requests to the vulnerable system.
The technical implementation of this vulnerability demonstrates a classic CSRF weakness that aligns with CWE-352, which specifically addresses cross-site request forgery conditions in web applications. The deleteuser function fails to implement proper request validation mechanisms such as anti-CSRF tokens, referer header checks, or origin validation. Attackers can craft malicious HTML pages or scripts that automatically submit deletion requests to the target system when users visit compromised websites. This vulnerability operates at the application layer and can be exploited without requiring any special privileges or authentication credentials. The flaw represents a fundamental security oversight in the web application's input validation and request processing logic, where the system fails to distinguish between legitimate administrative requests and maliciously crafted ones. The system's trust model is compromised because it accepts requests without proper verification of the request source or user authorization.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential complete system compromise and data loss. When exploited successfully, attackers can delete user accounts which may include administrators, thereby reducing system functionality and potentially creating access control gaps. The vulnerability can be leveraged to create persistent service disruptions by repeatedly deleting critical user accounts, effectively rendering portions of the telephony system unusable. Additionally, the ability to manipulate user accounts can lead to unauthorized access to system resources and potentially provide a foothold for further attacks. Organizations using this version of issabel-pbx face significant risk of service interruption and unauthorized system access. The vulnerability can be exploited remotely without requiring physical access to the system, making it particularly concerning for networked telephony environments. The impact is exacerbated by the fact that PBX systems often serve as critical communication infrastructure within organizations, making service disruption potentially catastrophic.
Mitigation strategies for CVE-2023-37596 should focus on immediate implementation of anti-CSRF protection mechanisms within the affected issabel-pbx system. Organizations should deploy anti-CSRF tokens for all state-changing operations including the deleteuser function, ensuring that each request includes a unique token that validates the user's legitimate intent. The system should implement proper referer header validation and origin checking to prevent requests from unauthorized domains. Network-level protections such as web application firewalls should be deployed to monitor and block suspicious requests to the vulnerable endpoint. Regular security updates and patches should be applied immediately upon availability from the software vendor. System administrators should also implement monitoring for unusual deletion patterns and user account modifications. The ATT&CK framework categorizes this vulnerability under T1566 for credential access and T1499 for network denial of service, highlighting the multi-faceted attack surface. Additional defensive measures include restricting access to administrative functions through network segmentation, implementing strong authentication mechanisms, and conducting regular security assessments to identify similar vulnerabilities in other system components. Organizations should also establish incident response procedures specifically addressing CSRF attacks to ensure rapid response and remediation when such vulnerabilities are exploited.