CVE-2009-1093 in JRE
Summary
by MITRE
LdapCtx in the LDAP service in Java SE Development Kit (JDK) and Java Runtime Environment (JRE) 5.0 Update 17 and earlier; 6 Update 12 and earlier; SDK and JRE 1.3.1_24 and earlier; and 1.4.2_19 and earlier does not close the connection when initialization fails, which allows remote attackers to cause a denial of service (LDAP service hang).
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Analysis
by VulDB Data Team • 08/09/2021
The vulnerability identified as CVE-2009-1093 resides within the LDAP service implementation of various Java runtime environments including JDK and JRE versions spanning from early releases through specific update versions. This flaw manifests in the LdapCtx component which handles LDAP connections and operations within the Java platform. The core issue emerges during the initialization phase of LDAP connections where the system fails to properly terminate network connections when authentication or connection establishment processes encounter failures. This represents a classic resource management flaw that violates fundamental security principles of proper connection handling and cleanup.
The technical nature of this vulnerability stems from inadequate connection lifecycle management within the LDAP service implementation. When an LDAP connection attempt fails during initialization, the LdapCtx component does not execute the necessary cleanup procedures to close the underlying network connection. This results in connection handles remaining open and active in the system's connection pool, creating a resource leak condition that accumulates over time. The vulnerability specifically affects multiple Java versions including 1.3.1_24 and earlier, 1.4.2_19 and earlier, 5.0 Update 17 and earlier, and 6 Update 12 and earlier releases, indicating a widespread issue across the Java platform's LDAP implementation.
From an operational perspective, this vulnerability enables remote attackers to execute a denial of service attack against systems running affected Java versions. The attack works by repeatedly initiating LDAP connection attempts that fail during initialization, causing the system to accumulate open connections that never get properly closed. Over time, this leads to exhaustion of available connection resources and system performance degradation, ultimately resulting in service unavailability. The impact is particularly severe in environments where LDAP services are frequently accessed or where the application relies heavily on LDAP for authentication and directory services, as the resource exhaustion can effectively bring the entire LDAP service to a halt.
The vulnerability aligns with CWE-404, which addresses improper resource cleanup or release, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Organizations utilizing affected Java versions face significant operational risks, particularly in enterprise environments where LDAP services are integral to authentication and directory operations. The attack vector is straightforward and requires minimal technical expertise, making it particularly dangerous as it can be exploited by attackers with basic network knowledge. The resource leak behavior creates a progressive degradation that may initially go unnoticed but eventually leads to complete service disruption, making this vulnerability particularly insidious in production environments.
Mitigation strategies include immediate application of security patches and updates provided by Oracle for the affected Java versions, implementing connection timeout configurations to limit the duration of hanging connections, and monitoring LDAP service connections for unusual patterns that may indicate resource exhaustion. System administrators should also consider implementing connection pooling limits and resource monitoring to detect and prevent the accumulation of stale connections. Additionally, network-level firewalls and intrusion detection systems can be configured to monitor for excessive LDAP connection attempts that may indicate exploitation attempts. The most effective long-term solution involves migrating to supported Java versions that have addressed this vulnerability and implementing comprehensive resource management practices for all network service connections.