CVE Vulnerabilities

CVE-2023-27371

Out-of-bounds Read

Published: Feb 28, 2023 | Modified: Mar 31, 2023
CVSS 3.x
5.9
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
5.9 MODERATE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM

GNU libmicrohttpd before 0.9.76 allows remote DoS (Denial of Service) due to improper parsing of a multipart/form-data boundary in the postprocessor.c MHD_create_post_processor() method. This allows an attacker to remotely send a malicious HTTP POST packet that includes one or more 0 bytes in a multipart/form-data boundary field, which - assuming a specific heap layout - will result in an out-of-bounds read and a crash in the find_boundary() function.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name Vendor Start Version End Version
Libmicrohttpd Gnu * 0.9.76 (excluding)
Red Hat Enterprise Linux 8 RedHat libmicrohttpd-1:0.9.59-3.el8 *
Red Hat Enterprise Linux 8.6 Extended Update Support RedHat libmicrohttpd-1:0.9.59-2.el8_6.1 *
Red Hat Enterprise Linux 8.8 Extended Update Support RedHat libmicrohttpd-1:0.9.59-2.el8_8.1 *
Red Hat Enterprise Linux 9 RedHat libmicrohttpd-1:0.9.72-5.el9 *
Libmicrohttpd Ubuntu bionic *
Libmicrohttpd Ubuntu kinetic *
Libmicrohttpd Ubuntu lunar *
Libmicrohttpd Ubuntu trusty *
Libmicrohttpd Ubuntu upstream *
Libmicrohttpd Ubuntu xenial *

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.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

References