CVE-2018-0308 in FXOS
Summary
by MITRE
A vulnerability in the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition. The vulnerability exists because the affected software insufficiently validates header values in Cisco Fabric Services packets. An attacker could exploit this vulnerability by sending a crafted Cisco Fabric Services packet to an affected device. A successful exploit could allow the attacker to cause a buffer overflow that could allow the attacker to execute arbitrary code or cause a DoS condition. This vulnerability affects the following if configured to use Cisco Fabric Services: Firepower 4100 Series Next-Generation Firewalls, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvd69954, CSCve02463, CSCve02785, CSCve02787, CSCve02804, CSCve04859.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/28/2023
This vulnerability resides within the Cisco Fabric Services component of Cisco FXOS Software and Cisco NX-OS Software, representing a critical security flaw that enables unauthenticated remote code execution or denial of service conditions. The underlying technical issue stems from inadequate validation of header values within Cisco Fabric Services packets, creating a pathway for malicious actors to manipulate the system through crafted network traffic. The vulnerability manifests as a buffer overflow condition that occurs when the affected software processes malformed header values, allowing attackers to overwrite memory segments and potentially execute arbitrary code with elevated privileges. This flaw affects a broad range of Cisco networking equipment including next-generation firewalls, multilayer switches, fabric interconnects, and various series of switches across multiple platforms. The impact extends to devices configured with Cisco Fabric Services functionality, making it particularly concerning for enterprise networks where these components are commonly deployed.
The exploitation of this vulnerability follows a well-defined attack pattern that aligns with the MITRE ATT&CK framework's technique T1203 - Exploitation for Client Execution and T1499 - Endpoint Denial of Service. Attackers can leverage this weakness by sending specifically crafted Cisco Fabric Services packets to vulnerable devices, bypassing authentication requirements entirely. The buffer overflow condition creates a scenario where attacker-controlled data can overwrite critical memory locations, potentially leading to arbitrary code execution or system crashes. This vulnerability represents a classic example of a remote code execution flaw that can be exploited without any prior authentication credentials, making it particularly dangerous in network environments where such services are exposed to untrusted networks. The affected devices include critical infrastructure components such as Firepower 4100 Series Next-Generation Firewalls, MDS 9000 Series Multilayer Switches, and various Nexus series switches, all of which form the backbone of enterprise network security and connectivity.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise entire network infrastructures, as demonstrated by the wide array of affected Cisco products. Organizations running vulnerable software may face unauthorized access to critical network devices, leading to potential data breaches, network disruption, or complete system compromise. The vulnerability's presence across multiple product lines including security appliances, switching platforms, and fabric interconnects means that organizations may have multiple attack vectors to defend against simultaneously. This creates a complex security management scenario where administrators must address the vulnerability across various device types and software versions, potentially requiring coordinated patching efforts across the entire network infrastructure. The lack of authentication requirements for exploitation means that even networks with proper access controls may be vulnerable if Cisco Fabric Services is enabled and accessible from untrusted networks.
Mitigation strategies for this vulnerability should include immediate implementation of network segmentation to restrict access to Cisco Fabric Services ports, disabling the affected functionality where possible, and applying the relevant Cisco security patches as released through their official vulnerability advisories. Organizations should also implement network monitoring to detect anomalous Cisco Fabric Services traffic patterns that could indicate exploitation attempts, utilizing intrusion detection systems to identify potential attacks. The vulnerability's classification as a buffer overflow aligns with CWE-121 - Stack-based Buffer Overflow, indicating that defensive programming practices such as bounds checking and input validation should be implemented at multiple levels. Network administrators should also consider implementing access control lists to restrict traffic to specific IP addresses or ranges that require access to Fabric Services functionality, and should regularly audit their network configurations to ensure that unnecessary services are disabled. The Cisco Bug IDs associated with this vulnerability (CSCvd69954, CSCve02463, CSCve02785, CSCve02787, CSCve02804, CSCve04859) indicate that multiple versions were affected, requiring careful version management and patch coordination across the enterprise network infrastructure.