CVE Vulnerabilities

CVE-2023-31473

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

Published: May 11, 2023 | Modified: May 22, 2023
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
RedHat/V2
RedHat/V3
Ubuntu

An issue was discovered on GL.iNet devices before 3.216. There is an arbitrary file write in which an empty file can be created anywhere on the filesystem. This is caused by a command injection vulnerability with a filter applied. Through the software installation feature, it is possible to inject arbitrary parameters in a request to cause opkg to read an arbitrary file name while using root privileges. The -f option can be used with a configuration file.

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
Gl-s20_firmware Gl-inet * *

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