CVE-2014-3004
Description
From CVE.org
The default configuration for the Xerces SAX Parser in Castor before 1.3.3 allows context-dependent attackers to conduct XML External Entity (XXE) attacks via a crafted XML document.
Statement
This issue affects the version of castor as shipped with Red Hat Enterprise Linux 5 and 6. The Red Hat Security Response Team has rated this issue as having Moderate security impact. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Red Hat JBoss SOA Platform 4 is now in Phase 3, Extended Life Support, of its life cycle. This issue has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat JBoss Middleware and Red Hat JBoss Operations Network Product Update and Support Policy: https://access.redhat.com/support/policy/updates/jboss_notes/
Fuse ESB Enterprise 7 is now in Maintenance Support phase receiving only qualified Important and Critical impact security fixes. This issue has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Fuse Product Life Cycle: https://access.redhat.com/support/policy/updates/fusesource/
Mitigation
"A configuration file in the Java library directory (e.g. /jdk1.2/lib) can be used to override the default configuration file with system-wide properties. In addition, a configuration file can be placed in the classpath and will override both the system wide properties and Castor-default configuration." [1]
Adding the following content in any of the above mentioned configuration files will act as a viable mitigation against this flaw.
> org.exolab.castor.sax.features=\
> http://apache.org/xml/features/disallow-doctype-decl
>
> org.exolab.castor.sax.features-to-disable=\
> http://xml.org/sax/features/external-general-entities,\
> http://xml.org/sax/features/external-parameter-entities,\
> http://apache.org/xml/features/nonvalidating/load-external-dtd
Note that using this configuration after upgrading to a version of Castor containing a fix for this issue might override any future hardening or changes to default behavior.
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 v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5 | 4.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Low | Medium | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Partial | Partial | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: AV:N/AC:L/Au:N/C:P/I:N/A:N
NVD: AV:N/AC:M/Au:N/C:P/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system. By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as "file:///c:/winnt/win.ini" designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g., in an error message), thereby exposing the file contents.
Integrity
Technical Impact: Bypass Protection Mechanism
An attacker may supply a crafted DTD using URIs with schemes such as http://, forcing the application to make outgoing HTTP requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions; hide the source of attacks such as port scanning; or otherwise leverage the server's trust relationship with other entities.
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
The product could consume excessive CPU cycles or memory using a URI that points to a large file, or a device that always returns data such as /dev/random. Alternately, the URI could reference a file that contains many nested or recursive entity references to further slow down parsing.
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