CVE-2006-5479 in eDirectory
Summary
by MITRE
The NCP Engine in Novell eDirectory before 8.7.3.8 FTF1 allows remote attackers to cause an unspecified denial of service via a certain "NCP Fragment."
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Analysis
by VulDB Data Team • 04/25/2026
The vulnerability identified as CVE-2006-5479 affects the NCP Engine within Novell eDirectory software versions prior to 8.7.3.8 FTF1, representing a significant security weakness that enables remote attackers to execute denial of service attacks. This flaw specifically targets the Network Client Protocol engine which handles network communications and packet processing within the eDirectory framework. The vulnerability manifests through a particular "NCP Fragment" that when transmitted to the affected system can trigger unexpected behavior leading to service disruption. The NCP Engine serves as a critical component for network communication in Novell environments, making this vulnerability particularly dangerous as it can impact the availability of directory services across enterprise networks.
The technical nature of this vulnerability stems from inadequate input validation and processing within the NCP Fragment handling mechanism. When an attacker sends a specially crafted NCP Fragment to a vulnerable eDirectory server, the system fails to properly handle the malformed packet, resulting in a denial of service condition that can cause the NCP Engine to crash or become unresponsive. This processing failure occurs at the protocol level where the engine does not implement proper bounds checking or state validation for incoming fragments. The vulnerability aligns with CWE-129, which describes issues related to insufficient validation of length fields in input processing, and represents a classic example of how malformed network traffic can be exploited to disrupt service availability. The attack vector is remote and requires no authentication, making it particularly dangerous in networked environments where the eDirectory server is accessible to untrusted parties.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the integrity of enterprise directory services that rely on Novell eDirectory for user authentication, authorization, and resource management. Organizations using affected versions of eDirectory may experience complete service outages that affect thousands of users and applications dependent on directory services. The vulnerability can be exploited by attackers to systematically disable directory services, potentially leading to cascading failures in network infrastructure that depends on these services for proper operation. From an attack methodology perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network disruption attacks targeting service availability, and represents a straightforward exploitation pattern that requires minimal technical skill to execute successfully.
Mitigation strategies for CVE-2006-5479 primarily focus on upgrading to Novell eDirectory version 8.7.3.8 FTF1 or later, which contains the necessary patches to address the NCP Fragment processing flaw. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable eDirectory servers to untrusted networks, particularly by restricting direct access to the NCP ports and services. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, and intrusion detection systems should be configured to alert on suspicious NCP Fragment patterns. Additionally, administrators should consider implementing firewall rules that filter out malformed or unexpected network traffic destined for directory services, and maintain regular security assessments to identify other potential vulnerabilities in the directory service infrastructure. The patching process should be prioritized as part of routine security maintenance procedures, with careful testing to ensure compatibility with existing directory service configurations and applications.