CVE-2014-2140 in ONS 15454
Summary
by MITRE
Cisco ONS 15454 controller cards with software 9.6 and earlier allow remote attackers to cause a denial of service (card reset) via a TCP FIN attack that triggers file-descriptor exhaustion and a failure to open a CAL pipe, aka Bug ID CSCug97348.
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Analysis
by VulDB Data Team • 05/10/2026
The vulnerability identified as CVE-2014-2140 affects Cisco ONS 15454 controller cards operating with software versions 9.6 and earlier, representing a significant denial of service weakness that can be exploited remotely by attackers. This flaw manifests through a specific TCP FIN attack pattern that systematically exhausts file descriptors on the affected system, ultimately preventing the successful establishment of CAL (Channel Access Layer) pipe connections essential for normal operation. The vulnerability operates at the network protocol level, leveraging the TCP connection termination mechanism to create a cascading failure condition that results in complete service disruption. The attack vector is particularly concerning as it requires no authentication or privileged access, making it accessible to any remote attacker with network connectivity to the affected device.
The technical implementation of this vulnerability stems from inadequate resource management within the controller card's TCP stack implementation. When a malicious TCP FIN packet is received, the system fails to properly handle the connection termination event, leading to a progressive exhaustion of available file descriptors. This resource depletion prevents the system from creating new file descriptors required for establishing CAL pipe connections, which are fundamental to the controller card's operation and communication with other network elements. The flaw specifically impacts the CAL pipe creation process, where the system attempts to open communication channels for channel access layer operations but fails due to the exhausted file descriptor pool. This creates a self-reinforcing condition where the system becomes unable to process legitimate network traffic or maintain operational connections, effectively resetting the card and causing service interruption.
The operational impact of CVE-2014-2140 extends beyond simple service disruption to potentially compromise network reliability and availability in telecommunications environments. In production network infrastructure, controller cards form critical components of optical network switching systems, where their failure can result in widespread service degradation or complete network outages. The vulnerability's remote exploitability means that attackers can trigger the denial of service condition from anywhere on the network, without requiring physical access or network credentials. This characteristic significantly increases the attack surface and makes the vulnerability particularly dangerous in environments where network security controls may not adequately protect critical infrastructure components. The resulting card reset operation can take considerable time to recover from, potentially causing extended service interruptions that affect multiple network services and customer connections.
Organizations should implement immediate mitigations including network segmentation to isolate affected controller cards from untrusted networks, deployment of access control lists to filter malicious TCP FIN packets, and implementation of monitoring solutions to detect unusual file descriptor exhaustion patterns. The vulnerability aligns with CWE-400, which addresses improper handling of resource exhaustion conditions, and demonstrates characteristics consistent with ATT&CK technique T1499.004 related to network denial of service attacks. Regular software updates and patches should be applied to upgrade affected systems to versions that properly handle TCP connection termination events and prevent file descriptor exhaustion. Network administrators should also consider implementing intrusion detection systems that can identify and alert on TCP FIN-based attack patterns, as well as establishing automated recovery procedures to minimize service disruption during attack events. The vulnerability underscores the importance of robust resource management and proper error handling in network infrastructure software, particularly in mission-critical telecommunications equipment where reliability is paramount.