XML External Entity (XXE) Injection Affecting ca.uhn.hapi.fhir:org.hl7.fhir.dstu2016may package, versions [,6.4.0)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team

    Threat Intelligence

    EPSS
    0.05% (19th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk ID SNYK-JAVA-CAUHNHAPIFHIR-8366325
  • published 11 Nov 2024
  • disclosed 8 Nov 2024
  • credit allonsyintensely

How to fix?

Upgrade ca.uhn.hapi.fhir:org.hl7.fhir.dstu2016may to version 6.4.0 or higher.

Overview

Affected versions of this package are vulnerable to XML External Entity (XXE) Injection via XSLT transforms. An attacker can access sensitive information from the host system by processing an XML file with a malicious DTD tag ( ]>. All cases where org.hl7.fhir.core is being used on a host where external clients can submit XML are impacted.

Note: This is due to an incomplete fix of CVE-2024-45294.

Details

XXE Injection is a type of attack against an application that parses XML input. XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. By default, many XML processors allow specification of an external entity, a URI that is dereferenced and evaluated during XML processing. When an XML document is being parsed, the parser can make a request and include the content at the specified URI inside of the XML document.

Attacks can include disclosing local files, which may contain sensitive data such as passwords or private user data, using file: schemes or relative paths in the system identifier.

For example, below is a sample XML document, containing an XML element- username.

<xml>
<?xml version="1.0" encoding="ISO-8859-1"?>
   <username>John</username>
</xml>

An external XML entity - xxe, is defined using a system identifier and present within a DOCTYPE header. These entities can access local or remote content. For example the below code contains an external XML entity that would fetch the content of /etc/passwd and display it to the user rendered by username.

<xml>
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE foo [
   <!ENTITY xxe SYSTEM "file:///etc/passwd" >]>
   <username>&xxe;</username>
</xml>

Other XXE Injection attacks can access local resources that may not stop returning data, possibly impacting application availability and leading to Denial of Service.

CVSS Scores

version 4.0
version 3.1
Expand this section

Snyk

Recommended
7.7 high
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Attack Requirements (AT)
    None
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Confidentiality (VC)
    None
  • Integrity (VI)
    None
  • Availability (VA)
    None
  • Confidentiality (SC)
    High
  • Integrity (SI)
    None
  • Availability (SA)
    None