CVE Vulnerabilities

CVE-2020-14342

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

Published: Sep 09, 2020 | Modified: Nov 21, 2024
CVSS 3.x
7
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.4 MEDIUM
AV:L/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
7 LOW
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Ubuntu
LOW

It was found that cifs-utils mount.cifs was invoking a shell when requesting the Samba password, which could be used to inject arbitrary commands. An attacker able to invoke mount.cifs with special permission, such as via sudo rules, could use this flaw to escalate their privileges.

Weakness

The product 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
Cifs-utils Samba 5.6 (including) 6.10 (including)
Cifs-utils Ubuntu bionic *
Cifs-utils Ubuntu devel *
Cifs-utils Ubuntu esm-infra-legacy/trusty *
Cifs-utils Ubuntu esm-infra/xenial *
Cifs-utils Ubuntu focal *
Cifs-utils Ubuntu groovy *
Cifs-utils Ubuntu hirsute *
Cifs-utils Ubuntu impish *
Cifs-utils Ubuntu jammy *
Cifs-utils Ubuntu kinetic *
Cifs-utils Ubuntu lunar *
Cifs-utils Ubuntu mantic *
Cifs-utils Ubuntu noble *
Cifs-utils Ubuntu oracular *
Cifs-utils Ubuntu precise/esm *
Cifs-utils Ubuntu trusty *
Cifs-utils Ubuntu trusty/esm *
Cifs-utils Ubuntu upstream *
Cifs-utils Ubuntu xenial *

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