CVE-2016-9606
Description
It was discovered that under certain conditions RESTEasy could be forced to parse a request with YamlProvider, resulting in unmarshalling of potentially untrusted data. An attacker could possibly use this flaw execute arbitrary code with the permissions of the application using RESTEasy.
Statement
YamlProvider was removed the default list of providers to prevent a malicous user from requesting a payload be marshalled with Yaml. If marshalling of Yaml content is desired, add, or append a file with the name 'META-INF/services/javax.ws.rs.ext.Providers' to your WAR, or JAR with the contents 'org.jboss.resteasy.plugins.providers.YamlProvider'
If YamlProvider is re-added to the default list of providers it's recommended to add authentication, and authorization to the endpoint expecting Yaml content to prevent exploitation of this vulnerablilty.
Mitigation
Add authentication and authorization to any Resteasy endpoint which doesn't define a mime type, or defines a multipart mime type.
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 | 8.1 | 8.1 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.8 | 6.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Medium | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Partial | Partial | N/A |
| Integrity Impact | Partial | Partial | N/A |
| Availability Impact | Partial | Partial | N/A |
Vector
Red Hat: AV:N/AC:M/Au:N/C:P/I:P/A:P
NVD: AV:N/AC:M/Au:N/C:P/I:P/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
Acknowledgements
Red Hat would like to thank Moritz Bechler (AgNO3 GmbH & Co. KG) for reporting this issue.
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