CVE Vulnerabilities

CVE-2019-5918

Improper Restriction of XML External Entity Reference

Published: Mar 12, 2019 | Modified: Mar 13, 2019
CVSS 3.x
9.1
CRITICAL
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CVSS 2.x
8.5 HIGH
AV:N/AC:L/Au:N/C:P/I:N/A:C
RedHat/V2
RedHat/V3
Ubuntu

Nablarch 5 (5, and 5u1 to 5u13) allows remote attackers to conduct XML External Entity (XXE) attacks via unspecified vectors.

Weakness

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

Affected Software

Name Vendor Start Version End Version
Nablarch Nablarch_project 5 (including) 5 (including)
Nablarch Nablarch_project 5u1 (including) 5u1 (including)
Nablarch Nablarch_project 5u13 (including) 5u13 (including)

Extended Description

XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of XML entities. It is possible to define an entity by providing a substitution string in the form of a URI. The XML parser can access the contents of this URI and embed these contents back into the XML document for further processing. 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. Using URIs with other schemes such as http://, the attacker can force the application to make outgoing requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions or hide the source of attacks such as port scanning. 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.

Potential Mitigations

References