CVE-2013-4590
Description
It was found that several application-provided XML files, such as web.xml, content.xml, *.tld, *.tagx, and *.jspx, resolved external entities, permitting XML External Entity (XXE) attacks. An attacker able to deploy malicious applications to Tomcat could use this flaw to circumvent security restrictions set by the JSM, and gain access to sensitive information on the system. Note that this flaw only affected deployments in which Tomcat is running applications from untrusted sources, such as in a shared hosting environment.
Statement
This issue did not affect JBoss Web, as shipped with various Red Hat JBoss products.
This issue does affect Tomcat 5 as shipped by Red Hat Enterprise Linux 5. The risks in breaking compatibility associated with fixing this flaw outweigh the benefits of the fix, therefore Red Hat does not plan to fix this flaw in Red Hat Enterprise Linux 5. Additionally, note that Red Hat Enterprise Linux 5 is currently in reduced support phase, receiving only Critical security updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/site/support/policy/updates/errata#Production_3_Phase
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 v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 1.2 | 4.3 | N/A |
| Attack Vector | Local | Network | N/A |
| Access Complexity | High | 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:L/AC:H/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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