CVE-2012-1339 in Unified Computing System Software
Summary
by MITRE
The Fabric Interconnect component in Cisco Unified Computing System (UCS) 2.0 allows remote attackers to cause a denial of service (process crash) via an attempted SSH session, aka Bug ID CSCtt94543.
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Analysis
by VulDB Data Team • 01/11/2018
The vulnerability identified as CVE-2012-1339 affects the Fabric Interconnect component within Cisco Unified Computing System version 2.0, representing a significant security weakness that enables remote attackers to execute denial of service attacks. This flaw specifically manifests during SSH session attempts, where malicious actors can trigger process crashes that disrupt normal system operations. The vulnerability resides in the SSH daemon implementation of the Fabric Interconnect, which fails to properly handle certain malformed or crafted SSH connection requests, leading to unexpected termination of critical processes.
This technical flaw operates through a buffer overflow or improper input validation mechanism within the SSH service implementation, where the system does not adequately sanitize incoming SSH protocol data. When an attacker establishes an SSH connection attempt, the Fabric Interconnect processes the connection request without sufficient validation checks, allowing malicious input to cause memory corruption or resource exhaustion that ultimately results in process termination. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication credentials, making it accessible to any attacker with network access to the system's SSH port.
The operational impact of this vulnerability extends beyond simple service disruption, as the Fabric Interconnect serves as a critical component in UCS infrastructure responsible for managing network connectivity and fabric switching operations. When the SSH process crashes, administrators lose remote management capabilities, potentially leading to extended downtime while system recovery procedures are executed. The denial of service condition affects not only the SSH service but may also impact the overall stability of the UCS fabric, potentially causing network disruptions for connected servers and applications. This vulnerability directly relates to CWE-121, which addresses stack-based buffer overflow conditions, and may also involve CWE-20, representing improper input validation issues.
Organizations affected by this vulnerability face substantial operational risks including extended service interruptions, potential data loss during recovery operations, and increased administrative overhead required to maintain system availability. The remote exploit nature means that attackers can target systems from outside the network perimeter, making traditional network-based defenses insufficient to prevent exploitation. Security professionals should consider this vulnerability in relation to ATT&CK technique T1499, which encompasses network denial of service attacks, and T1566, covering social engineering tactics that could be used to establish initial access for exploitation. The vulnerability also demonstrates the importance of implementing proper input validation and secure coding practices in network infrastructure components, as highlighted in various security frameworks including NIST SP 800-53 and ISO 27001 standards.
Mitigation strategies should include immediate deployment of Cisco's official security patches and updates, implementation of network segmentation to limit SSH access to trusted administrative networks, and deployment of intrusion detection systems to monitor for suspicious SSH connection patterns. Organizations should also consider implementing SSH access controls that limit connection attempts from specific IP ranges and establish monitoring procedures to detect process crashes or unusual system behavior. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network infrastructure components, ensuring comprehensive protection against similar remote exploitation techniques that could compromise system availability and integrity.