CVE-2018-5740
Description
A denial of service flaw was discovered in bind versions that include the "deny-answer-aliases" feature. This flaw may allow a remote attacker to trigger an INSIST assert in named leading to termination of the process and a denial of service condition.
Statement
The "deny-answer-aliases" configuration option is not enabled in default configurations of bind. Upstream states that this option is very rarely used. As such, if customers have not specifically enabled this option in configurations, the risk should be mitigated.
Mitigation
Disabling the "deny-answer-aliases" configuration option should prevent exploitation.
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 | 7.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Acknowledgements
Red Hat would like to thank ISC for reporting this issue. Upstream acknowledges Tony Finch (University of Cambridge) as the original reporter.
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