CVE Vulnerabilities

CVE-2020-3223

Improper Link Resolution Before File Access ('Link Following')

Published: Jun 03, 2020 | Modified: Jun 09, 2020
CVSS 3.x
4.9
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
6.8 MEDIUM
AV:N/AC:L/Au:S/C:C/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

A vulnerability in the web-based user interface (web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker with administrative privileges to read arbitrary files on the underlying filesystem of the device. The vulnerability is due to insufficient file scope limiting. An attacker could exploit this vulnerability by creating a specific file reference on the filesystem and then accessing it through the web UI. An exploit could allow the attacker to read arbitrary files from the underlying operating systems filesystem.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Ios_xe Cisco 16.9.4 (including) 16.9.4 (including)
Ios_xe Cisco 16.9.4c (including) 16.9.4c (including)
Ios_xe Cisco 16.11.1 (including) 16.11.1 (including)
Ios_xe Cisco 16.11.1a (including) 16.11.1a (including)
Ios_xe Cisco 16.11.1b (including) 16.11.1b (including)
Ios_xe Cisco 16.11.1c (including) 16.11.1c (including)
Ios_xe Cisco 16.11.1s (including) 16.11.1s (including)
Ios_xe Cisco 16.11.2 (including) 16.11.2 (including)
Ios_xe Cisco 16.12.1 (including) 16.12.1 (including)
Ios_xe Cisco 16.12.1a (including) 16.12.1a (including)
Ios_xe Cisco 16.12.1c (including) 16.12.1c (including)
Ios_xe Cisco 16.12.1s (including) 16.12.1s (including)
Ios_xe Cisco 16.12.1t (including) 16.12.1t (including)
Ios_xe Cisco 16.12.1w (including) 16.12.1w (including)
Ios_xe Cisco 16.12.1y (including) 16.12.1y (including)

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References