CVE-2017-14495
Description
A memory exhaustion flaw was found in dnsmasq in the EDNS0 code. An attacker could send crafted DNS packets which would trigger memory allocations which would never be freed, leading to unbounded memory consumption and eventually a crash. This issue only affected configurations using one of the options: add-mac, add-cpe-id, or add-subnet.
Statement
Red Hat OpenStack Platform includes the dnsmasq-utils RPM which does not contain this flaw's affected code-paths; Red Hat OpenStack Platform is therefore listed as not affected.
However, because all versions of Red Hat OpenStack Platform are based on Red Hat Enterprise Linux, all Red Hat OpenStack Platform users should absolutely upgrade the dnsmasq RPM from Red Hat Enterprise Linux as a matter of urgency using standard update mechanisms (such as 'yum update' or 'openstack overcloud update').
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.8 | 5 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Low | Low | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Complete | Partial | N/A |
Vector
Red Hat: AV:N/AC:L/Au:N/C:N/I:N/A:C
NVD: AV:N/AC:L/Au:N/C:N/I:N/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an attacker can trigger the allocation of the limited resources, but the number or size of the resources is not controlled, then the most common result is denial of service. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment, i.e., the product may slow down, crash due to unhandled errors, or lock out legitimate users. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.
Access Control,Other
Technical Impact: Bypass Protection Mechanism; Other
In some cases it may be possible to force the product to "fail open" in the event of resource exhaustion. The state of the product -- and possibly the security functionality - may then be compromised.
Acknowledgements
Red Hat would like to thank Felix Wilhelm (Google Security Team), Fermin J. Serna (Google Security Team), Gabriel Campana (Google Security Team), Kevin Hamacher (Google Security Team), and Ron Bowes (Google Security Team) for reporting this issue.
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