CVE Vulnerabilities

CVE-2020-5363

Improper Neutralization of Null Byte or NUL Character

Published: Jun 10, 2020 | Modified: Nov 21, 2024
CVSS 3.x
6.7
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

Select Dell Client Consumer and Commercial platforms include an issue that allows the BIOS Admin password to be changed through Dells manageability interface without knowledge of the current BIOS Admin password. This could potentially allow an unauthorized actor, with physical access and/or OS administrator privileges to the device, to gain privileged access to the platform and the hard drive.

Weakness

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.

Affected Software

Name Vendor Start Version End Version
Latitude_5300_firmware Dell * 1.9.4 (excluding)

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