CVE-2008-6576 in CS1000
Summary
by MITRE
Unspecified vulnerability in the "session limitation technique" in the FTP service on Nortel Communications Server 1000 (CS1K) 4.50.x, when running on VGMC or signaling nodes, allows remote attackers to cause a denial of service (resource exhaustion and failed updates) via unknown vectors that causes consumption of all available sessions.
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Analysis
by VulDB Data Team • 11/03/2018
The vulnerability described in CVE-2008-6576 represents a critical flaw in the session management mechanism of Nortel Communications Server 1000 (CS1K) version 4.50.x systems. This issue specifically affects FTP services operating on either VGMC or signaling nodes within the communication infrastructure, creating a potential pathway for remote attackers to exploit the system's session limitation technique. The vulnerability falls under the category of unspecified weakness that directly impacts the fundamental resource management capabilities of the network infrastructure component.
The technical flaw manifests through an improper implementation of session limitation controls within the FTP service daemon. When attackers exploit this weakness, they can manipulate the session handling mechanism to consume all available session resources on the affected system. This particular implementation flaw allows for the exhaustion of session limits without proper validation or rate limiting controls, enabling an attacker to flood the system with session requests until no resources remain for legitimate operations. The vulnerability operates at the protocol level where the system fails to properly enforce session constraints, creating a scenario where malicious actors can systematically deplete the session pool through unknown but exploitable vectors.
From an operational perspective, this vulnerability creates severe consequences for network availability and service continuity. The denial of service attack resulting from resource exhaustion can prevent legitimate users from establishing FTP connections while also causing failed updates to the system itself. The impact extends beyond simple connection denial, as the system's ability to maintain stable operations and perform necessary maintenance tasks becomes compromised. This vulnerability directly affects the availability and reliability of critical communication services that depend on the CS1K platform, potentially disrupting business operations and communication networks that rely on these infrastructure components.
The attack surface for this vulnerability is primarily accessible through network-based remote exploitation, making it particularly dangerous in environments where FTP services are exposed to untrusted networks. The unspecified nature of the attack vectors suggests multiple potential methods of exploitation that could include crafted session requests, connection flooding, or manipulation of session establishment parameters. This vulnerability aligns with CWE-400, which addresses improper resource management, and represents a classic example of resource exhaustion attacks that can be categorized under the ATT&CK technique T1499.1 for network denial of service. Organizations should implement immediate mitigations including network segmentation, firewall rules to restrict FTP access, and monitoring for unusual session patterns. The recommended approach involves applying vendor patches when available, implementing connection rate limiting, and establishing robust session monitoring to detect and prevent exploitation attempts before they can cause significant disruption to critical communication services.