CVE Vulnerabilities

CVE-2021-28323

Improper Handling of Case Sensitivity

Published: Apr 13, 2021 | Modified: Dec 29, 2023
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

Windows DNS Information Disclosure Vulnerability

Weakness

The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.

Affected Software

Name Vendor Start Version End Version
Windows_10 Microsoft - -
Windows_10 Microsoft 20h2 20h2
Windows_10 Microsoft 1607 1607
Windows_10 Microsoft 1803 1803
Windows_10 Microsoft 1809 1809
Windows_10 Microsoft 1909 1909
Windows_10 Microsoft 2004 2004
Windows_7 Microsoft - -
Windows_8.1 Microsoft - -
Windows_rt_8.1 Microsoft - -
Windows_server_2008 Microsoft - -
Windows_server_2008 Microsoft r2 r2
Windows_server_2012 Microsoft - -
Windows_server_2012 Microsoft r2 r2
Windows_server_2016 Microsoft - -
Windows_server_2016 Microsoft 20h2 20h2
Windows_server_2016 Microsoft 1909 1909
Windows_server_2016 Microsoft 2004 2004
Windows_server_2019 Microsoft - -

Extended Description

Improperly handled case sensitive data can lead to several possible consequences, including:

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