XML External Entity (XXE) Injection Affecting software.amazon.jdbc:aws-advanced-jdbc-wrapper package, versions [3.3.0,4.3.0)

software.amazon.jdbc:aws-advanced-jdbc-wrapper is an Amazon Web Services (AWS) Advanced JDBC Wrapper

Affected versions of this package are vulnerable to XML External Entity (XXE) Injection via the CachedSQLXML.getSource() path in wrapper/src/main/java/software/amazon/jdbc/plugin/cache/CachedSQLXML.java. An attacker can disclose files readable by the application process by writing a crafted XML payload into the shared RemoteQueryCachePlugin cache and then causing the application to read that cached value as SQLXML, such as through getSQLXML().getSource(). When the cached XML is parsed without disabling DTDs and external entity resolution, the XML parser resolves attacker-controlled entities during DOMSource, SAXSource, or StAXSource conversion. This can expose sensitive local data, including database credentials or IAM role credentials, to any application using the plugin with a writable shared Redis or Valkey cache.

Workarounds

• Disable the RemoteQueryCachePlugin so cached query results are no longer read from the shared Redis or Valkey cache; this removes the XXE attack path that depends on reading attacker-supplied XML from cache.
• Restrict write access to the Redis or Valkey cache infrastructure to trusted principals only; this prevents an attacker from planting crafted XML payloads into cache entries that the application later parses as SQLXML.

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.

• aws.amazon.com
• GitHub Commit 4.3.0
• Maintainer's Advisory