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CVE-2018-0301: Cisco NX OS: Authentication bypass

CVE-2018-0301 is rated critical with a CVSS v3.0 base score of 9.8 and affects Cisco NX OS. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an unauthenticated, remote attacker to craft a packet to the management interface on an affected system, causing a buffer overflow. The vulnerability is due to incorrect input validation in the authentication module of the NX-API subsystem. An attacker could exploit this vulnerability by sending a crafted HTTP or HTTPS packet to the management interface of an affected system with the NX-API feature enabled. An exploit could allow the attacker to execute arbitrary code as root. Note: NX-API is disabled by default. This vulnerability affects: 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. Cisco Bug IDs: CSCvd45804, CSCve02322, CSCve02412.

Severity breakdown

CVSS v3.0 9.8: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-20: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

Affected products

  • Cisco NX OS: from 6.0 before 7.3\(3\)n1\(1\); from 7.2 before 7.3\(2\)d1\(1\); from 8.0 before 8.1\(1\); 8.1; 8.2; before 7.0\(3\)i4; from 7.0\(3\)i5 before 7.0\(3\)i7\(1\); 7.0\(3\)i7; from 7.3 before 7.3\(3\)n1\(1\); 6.0; 7.0; 7.1

References