CVE-2009-4440 in Java System Directory Server
Summary
by MITRE
Directory Proxy Server (DPS) in Sun Java System Directory Server Enterprise Edition 6.0 through 6.3.1 does not properly handle multiple client connections within a short time window, which allows remote attackers to hijack the backend connection of an authenticated user, and obtain the privileges of this user, by making a client connection in opportunistic circumstances, related to "long binds," aka Bug Ids 6828462 and 6823593.
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Analysis
by VulDB Data Team • 08/30/2021
The vulnerability described in CVE-2009-4440 represents a critical security flaw in Sun Java System Directory Server Enterprise Edition versions 6.0 through 6.3.1 that specifically targets the directory proxy server component. This issue manifests through improper handling of concurrent client connections within brief time intervals, creating exploitable conditions that enable remote attackers to compromise authenticated user sessions. The vulnerability stems from the server's inadequate management of what are termed "long binds" in the directory service protocol, where extended connection sessions become susceptible to manipulation by malicious actors who time their connection attempts strategically to hijack existing backend connections.
The technical mechanism behind this vulnerability involves the server's connection management system failing to properly validate or isolate concurrent connections that occur within a narrow temporal window. When an authenticated user establishes a connection to the directory server, the system maintains a backend connection that persists for an extended period. Attackers can exploit this by establishing their own connection at precisely the right moment when the server is processing the authenticated user's session, allowing them to intercept and assume the privileges of the legitimate user. This type of attack falls under the category of session hijacking and privilege escalation, where the attacker essentially piggybacks on an existing authenticated session rather than attempting to brute force credentials.
The operational impact of this vulnerability is severe and multifaceted, as it allows attackers to gain unauthorized access to directory services with the privileges of legitimate authenticated users. This means that if an attacker successfully hijacks a connection from a user with administrative privileges, they could potentially access sensitive directory information, modify user accounts, manipulate access controls, or perform other malicious activities within the directory service environment. The vulnerability affects the core authentication and authorization mechanisms of the directory server, potentially compromising the entire directory service infrastructure that many enterprise applications depend upon for user management and access control. Organizations using affected versions of the Sun Java System Directory Server Enterprise Edition face significant risk of unauthorized access to their directory services, which could lead to data breaches, privilege escalation, and broader system compromise.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and relates to the broader category of session management weaknesses that attackers exploit to gain unauthorized access to systems. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, specifically targeting the T1078 (Valid Accounts) and T1566 (Phishing) tactics where attackers leverage legitimate credentials to maintain persistent access to systems. The exploitation of this vulnerability requires minimal network access and can be performed remotely, making it particularly dangerous as it allows attackers to operate without physical presence or direct system access. Organizations should implement immediate mitigations including upgrading to patched versions of the software, implementing connection rate limiting, and monitoring for suspicious connection patterns. The vulnerability also highlights the importance of proper session management and connection isolation in enterprise directory services, emphasizing the need for robust authentication systems that can prevent such temporal race conditions from being exploited by malicious actors.