CVE Vulnerabilities

CVE-2016-6911

Out-of-bounds Read

Published: Jan 26, 2017 | Modified: Nov 04, 2017
CVSS 3.x
5.5
MEDIUM
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.x
4.3 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P
RedHat/V2
4.3 MODERATE
AV:N/AC:M/Au:N/C:N/I:N/A:P
RedHat/V3
5.3 MODERATE
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Ubuntu
MEDIUM

The dynamicGetbuf function in the GD Graphics Library (aka libgd) before 2.2.4 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted TIFF image.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Libgd Libgd * 2.2.3 (including)
Libgd2 Ubuntu devel *
Libgd2 Ubuntu esm-infra/xenial *
Libgd2 Ubuntu precise *
Libgd2 Ubuntu trusty *
Libgd2 Ubuntu trusty/esm *
Libgd2 Ubuntu xenial *
Libgd2 Ubuntu yakkety *

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