Attacker Value
Low
(1 user assessed)
Exploitability
High
(1 user assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Adjacent_network
0

CVE-2020-3120 (AKA: CDPwn)

Disclosure Date: February 05, 2020 •
CVE-2020-3120 CVSS v3 Base Score: 6.5
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Description

A vulnerability in the Cisco Discovery Protocol implementation for Cisco FXOS Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing check when the affected software processes Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to exhaust system memory, causing the device to reload. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

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4
Ratings
  • Attacker Value
    Low
  • Exploitability
    High
Technical Analysis

This vulnerability can be used to trigger a memory exhaustion attack on affected routers within the CDP process. Once the process is out of memory it will crash and the router will reboot causing a denial of service condition for the network. Exploiting this vulnerability would not yield access to sensitive information or bypass segmentation (unless an improperly configured fail over setup is in place).

An attacker would need to be on the local area network, attached to the vulnerable router. This is due to CDP traffic not being forwarded across network boundaries. An attacker leveraging this vulnerability would likely either be physically in the building or have compromised a host which is physically in the building.

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CVSS V3 Severity and Metrics
Base Score:
6.5 Medium
Impact Score:
3.6
Exploitability Score:
2.8
Vector:
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Adjacent_network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Cisco IOS XR Software 2.3.1.173
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • cisco

Products

  • firepower extensible operating system,
  • fxos 2.4,
  • ios xr 5.2.5,
  • ios xr 6.4.2,
  • ios xr 6.5.3,
  • ios xr 6.6.25,
  • ios xr 7.0.1,
  • nx-os,
  • ucs manager
Technical Analysis