CVE-2018-0305 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 cause a denial of service (DoS) condition on the affected device. The vulnerability exists because the affected software insufficiently validates 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 force a NULL pointer dereference and 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: CSCvd69966, CSCve02435, CSCve04859, CSCve41590, CSCve41593, CSCve41601.
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Analysis
by VulDB Data Team • 03/28/2023
The vulnerability identified as CVE-2018-0305 represents a critical denial of service weakness within Cisco's Fabric Services component that affects multiple network infrastructure devices. This flaw resides in the Cisco FXOS Software and Cisco NX-OS Software implementations where the system fails to properly validate incoming Cisco Fabric Services packets. The vulnerability stems from insufficient input validation mechanisms that should normally filter and sanitize network traffic before processing. According to the Cisco Bug IDs associated with this issue, CSCvd69966 through CSCve41601, the problem manifests specifically when devices configured with Cisco Fabric Services receive malformed packets that trigger unexpected behavior in the software stack.
The technical exploitation of this vulnerability occurs through a carefully crafted Cisco Fabric Services packet that forces the system into a NULL pointer dereference condition. This type of error represents a classic software flaw where the application attempts to access memory at a null address, typically resulting in a system crash or reboot. The vulnerability's remote nature means that attackers do not require physical access or authentication credentials to exploit the flaw, making it particularly dangerous in networked environments. The NULL pointer dereference creates a condition where the software cannot properly handle the malformed packet, leading to an immediate system termination or restart cycle that effectively renders the device unavailable to legitimate users.
The operational impact of this vulnerability extends across numerous Cisco networking platforms, including high-end switches, firewalls, and fabric interconnects that form the backbone of enterprise network infrastructure. Devices such as Firepower 4100 Series Next-Generation Firewalls, MDS 9000 Series Multilayer Switches, and Nexus series switches all face potential disruption from this flaw. The widespread affected product line indicates that this vulnerability could compromise network availability on a large scale, potentially affecting critical business operations, network segmentation, and security posture. Organizations relying on these devices for core network functions would experience service interruptions that could last until the device is manually rebooted or the software patch is applied.
This vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions that can lead to system instability, and relates to the ATT&CK technique T1499.004 for "Endpoint Denial of Service" where adversaries target system resources to prevent legitimate use. The attack vector classification places this vulnerability under network-based exploitation requiring no authentication, making it particularly attractive to threat actors seeking to disrupt network operations. Mitigation strategies should include immediate implementation of Cisco's security advisories, network segmentation to isolate affected devices, and monitoring for unusual traffic patterns that might indicate exploitation attempts. Organizations should also consider applying the relevant software patches as soon as they become available to address the root cause of the validation failure in the Fabric Services component.