CVE Vulnerabilities

CVE-2020-11047

Out-of-bounds Read

Published: May 07, 2020 | Modified: Jun 09, 2020
CVSS 3.x
5.9
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:H
CVSS 2.x
4.9 MEDIUM
AV:N/AC:M/Au:S/C:P/I:N/A:P
RedHat/V2
RedHat/V3
5.9 MODERATE
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:H
Ubuntu

In FreeRDP after 1.1 and before 2.0.0, there is an out-of-bounds read in autodetect_recv_bandwidth_measure_results. A malicious server can extract up to 8 bytes of client memory with a manipulated message by providing a short input and reading the measurement result data. This has been patched in 2.0.0.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Freerdp Freerdp * *
Red Hat Enterprise Linux 7 RedHat freerdp-0:2.1.1-2.el7 *
Red Hat Enterprise Linux 8 RedHat freerdp-2:2.1.1-1.el8 *
Red Hat Enterprise Linux 8 RedHat vinagre-0:3.22.0-23.el8 *
Freerdp Ubuntu trusty *
Freerdp2 Ubuntu bionic *
Freerdp2 Ubuntu eoan *
Freerdp2 Ubuntu focal *
Freerdp2 Ubuntu trusty *

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