CVE-2016-8734
Description
From CVE.org
Apache Subversion's mod_dontdothat module and HTTP clients 1.4.0 through 1.8.16, and 1.9.0 through 1.9.4 are vulnerable to a denial-of-service attack caused by exponential XML entity expansion. The attack can cause the targeted process to consume an excessive amount of CPU resources or memory.
Mitigation
Only Apache+Subversion servers that have the "DontDoThatConfigFile" configuration option present are affected by this flaw. This option is not enabled in default httpd or mod_dav_svn configuration as shipped with Red Hat Enterprise Linux.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | High | Low | 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:H/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.5 | 4 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | Single | Single | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Partial | Partial | N/A |
Vector
Red Hat: AV:N/AC:M/Au:S/C:N/I:N/A:P
NVD: AV:N/AC:L/Au:S/C:N/I:N/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Other)
If parsed, recursive entity references allow the attacker to expand data exponentially, quickly consuming all system resources.
Acknowledgements
This issue was discovered by Florian Weimer (Red Hat).
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