XML External Entity (XXE) Injection Affecting org.apache.camel:camel-smooks package, versions [4.7.0,4.18.5)[4.19.0,4.22.1)

Affected versions of this package are vulnerable to XML External Entity (XXE) Injection through XML parsing in the Smooks data format (SmooksDataFormat) and smooks: component (SmooksProcessor) in camel-smooks. An attacker can read files accessible to the Camel process or make it send requests to internal network hosts by supplying an XML message body with an external entity declaration; when Smooks uses its default reader, it resolves the entity during unmarshalling and includes the resolved content in the result returned on InOut routes.

Notes

• The parsing step is affected only when Smooks uses its default XML reader; configurations declaring their own reader, such as EDI, CSV, JSON, or a custom reader, are not affected.

Workarounds

• Do not apply camel-smooks to XML received from untrusted senders; this prevents attacker-supplied external entities from being resolved to read local files or make requests to internal hosts.

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.

• Apache Jira Issues
• camel.apache.org
• GitHub Commit camel-4.18.5
• GitHub Commit camel-4.22.1
• GitHub Commit camel-4.23.0