CVE Vulnerabilities

CVE-2021-1514

Improper Neutralization of Special Elements used in a Command ('Command Injection')

Published: May 06, 2021 | Modified: Aug 27, 2021
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

A vulnerability in the CLI of Cisco SD-WAN Software could allow an authenticated, local attacker to inject arbitrary commands to be executed with Administrator privileges on the underlying operating system. This vulnerability is due to insufficient input validation on certain CLI commands. An attacker could exploit this vulnerability by authenticating to the device and submitting crafted input to the CLI. The attacker must be authenticated as a low-privileged user to execute the affected commands. A successful exploit could allow the attacker to execute commands with Administrator privileges.

Weakness

The software constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected Software

Name Vendor Start Version End Version
Sd-wan_vbond_orchestrator Cisco * *
Sd-wan_vbond_orchestrator Cisco 20.1 *
Sd-wan_vbond_orchestrator Cisco 20.3 *
Sd-wan_vbond_orchestrator Cisco 20.4 *
Sd-wan_vbond_orchestrator Cisco 20.5 *
Sd-wan_vmanage Cisco * *
Sd-wan_vmanage Cisco 20.1 *
Sd-wan_vmanage Cisco 20.3 *
Sd-wan_vmanage Cisco 20.4 *
Sd-wan_vmanage Cisco 20.5 *

Extended Description

Command injection vulnerabilities typically occur when:

Many protocols and products have their own custom command language. While OS or shell command strings are frequently discovered and targeted, developers may not realize that these other command languages might also be vulnerable to attacks. Command injection is a common problem with wrapper programs.

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

References