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Java: Query for detecting unsafe deserialization with Spring exporters #5260

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Original file line number Diff line number Diff line change
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@Configuration
public class Server {

@Bean(name = "/account")
HttpInvokerServiceExporter accountService() {
HttpInvokerServiceExporter exporter = new HttpInvokerServiceExporter();
exporter.setService(new AccountServiceImpl());
exporter.setServiceInterface(AccountService.class);
return exporter;
}

}

class AccountServiceImpl implements AccountService {

@Override
public String echo(String data) {
return data;
}
}

interface AccountService {
String echo(String data);
}
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<bean name="/account" class="org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter">
<property name="service" ref="accountService"/>
<property name="serviceInterface" value="AccountService"/>
</bean>
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<include src="UnsafeSpringExporterQuery.inc.qhelp" />
<include src="UnsafeSpringExporterInConfigurationClassExample.inc.qhelp" />
<include src="UnsafeSpringExporterReferences.inc.qhelp" />
</qhelp>
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/**
* @name Unsafe deserialization with Spring's remote service exporters.
* @description A Spring bean, which is based on RemoteInvocationSerializingExporter,
* initializes an endpoint that uses ObjectInputStream to deserialize
* incoming data. In the worst case, that may lead to remote code execution.
* @kind problem
* @problem.severity error
* @precision high
* @id java/unsafe-deserialization-spring-exporter-in-configuration-class
* @tags security
* external/cwe/cwe-502
*/

import java
import UnsafeSpringExporterLib

/**
* A method that initializes a unsafe bean based on `RemoteInvocationSerializingExporter`.
*/
private class UnsafeBeanInitMethod extends Method {
string identifier;

UnsafeBeanInitMethod() {
isRemoteInvocationSerializingExporter(this.getReturnType()) and
this.getDeclaringType().hasAnnotation("org.springframework.context.annotation", "Configuration") and
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We need to account for @Configuration meta-annotations such as @SpringBootApplication or maybe its enough to consider that @Bean annotations are going to be placed in the right classes and remove the check for @Configuration altogether

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That's a very good point @pwntester ! I've updated the query to take into account meta-annotations that has @Configuration.

exists(Annotation a |
a.getType().hasQualifiedName("org.springframework.context.annotation", "Bean")
|
this.getAnAnnotation() = a and
if a.getValue("name") instanceof StringLiteral
then identifier = a.getValue("name").(StringLiteral).getRepresentedString()
else identifier = this.getName()
)
}

string getBeanIdentifier() { result = identifier }
artem-smotrakov marked this conversation as resolved.
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}

from UnsafeBeanInitMethod method
select method,
"Unsafe deserialization in a Spring exporter bean '" + method.getBeanIdentifier() + "'"
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>

<example>
<p>
The following example shows how a vulnerable HTTP endpoint can be defined
using <code>HttpInvokerServiceExporter</code> and Spring annotations:
</p>
<sample src="SpringExporterUnsafeDeserialization.java" />
</example>

</qhelp>
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<include src="UnsafeSpringExporterQuery.inc.qhelp" />
<include src="UnsafeSpringExporterInXMLConfigurationExample.inc.qhelp" />
<include src="UnsafeSpringExporterReferences.inc.qhelp" />
</qhelp>
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/**
* @name Unsafe deserialization with Spring's remote service exporters.
* @description A Spring bean, which is based on RemoteInvocationSerializingExporter,
* initializes an endpoint that uses ObjectInputStream to deserialize
* incoming data. In the worst case, that may lead to remote code execution.
* @kind problem
* @problem.severity error
* @precision high
* @id java/unsafe-deserialization-spring-exporter-in-xml-configuration
* @tags security
* external/cwe/cwe-502
*/

import java
import semmle.code.java.frameworks.spring.SpringBean
import UnsafeSpringExporterLib

from SpringBean bean
where isRemoteInvocationSerializingExporter(bean.getClass())
select bean, "Unsafe deserialization in a Spring exporter bean '" + bean.getBeanIdentifier() + "'"
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>

<example>
<p>
The following examples shows how a vulnerable HTTP endpoint can be defined in a Spring XML config:
</p>
<sample src="SpringExporterUnsafeDeserialization.xml" />
</example>

</qhelp>
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import java

/**
* Holds if `type` is `RemoteInvocationSerializingExporter`.
*/
predicate isRemoteInvocationSerializingExporter(RefType type) {
type.getASupertype*()
.hasQualifiedName("org.springframework.remoting.rmi", "RemoteInvocationSerializingExporter")
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@artem-smotrakov just found a vulnerability on an application using the RMIServiceExporter and then remembered this PR. I think it would be nice to extend it so that it includes other vulnerable exporters such as the RmiBasedExporter or the HessianExporter

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Good point! Here you go #6142 Thanks!

}
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>

<overview>
<p>
The Spring Framework provides an abstract base class <code>RemoteInvocationSerializingExporter</code>
for creating remote service exporters.
A Spring exporter, which is based on this class, deserializes incoming data using <code>ObjectInputStream</code>.
Deserializing untrusted data is easily exploitable and in many cases allows an attacker
to execute arbitrary code.
</p>
<p>
The Spring Framework also provides <code>HttpInvokerServiceExporter</code>
and <code>SimpleHttpInvokerServiceExporter</code> classes
that extend <code>RemoteInvocationSerializingExporter</code>.
</p>
<p>
These classes export specified beans as HTTP endpoints that deserialize data from an HTTP request
using unsafe <code>ObjectInputStream</code>. If a remote attacker can reach such endpoints,
it results in remote code execution in the worst case.
</p>
<p>
CVE-2016-1000027 has been assigned to this issue in the Spring Framework.
It is regarded as a design limitation, and can be mitigated but not fixed outright.
</p>
</overview>

<recommendation>
<p>
Avoid using <code>HttpInvokerServiceExporter</code>, <code>SimpleHttpInvokerServiceExporter</code>
and any other exporter that is based on <code>RemoteInvocationSerializingExporter</code>.
Instead, use other message formats for API endpoints (for example, JSON),
but make sure that the underlying deserialization mechanism is properly configured
so that deserialization attacks are not possible. If the vulnerable exporters can not be replaced,
consider using global deserialization filters introduced in JEP 290.
</p>
</recommendation>

</qhelp>
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<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>

<references>
<li>
OWASP:
<a href="https://www.owasp.org/index.php/Deserialization_of_untrusted_data">Deserialization of untrusted data</a>.
</li>
<li>
Spring Framework API documentation:
<a href="https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/remoting/rmi/RemoteInvocationSerializingExporter.html">RemoteInvocationSerializingExporter class</a>
</li>
<li>
Spring Framework API documentation:
<a href="https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/remoting/httpinvoker/HttpInvokerServiceExporter.html">HttpInvokerServiceExporter class</a>
</li>
<li>
National Vulnerability Database:
<a href="https://nvd.nist.gov/vuln/detail/CVE-2016-1000027">CVE-2016-1000027</a>
</li>
<li>
Tenable Research Advisory:
<a href="https://www.tenable.com/security/research/tra-2016-20">[R2] Pivotal Spring Framework HttpInvokerServiceExporter readRemoteInvocation Method Untrusted Java Deserialization</a>
</li>
<li>
Spring Framework bug tracker:
<a href="https://github.com/spring-projects/spring-framework/issues/24434">Sonatype vulnerability CVE-2016-1000027 in Spring-web project</a>
</li>
<li>
OpenJDK:
<a href="https://openjdk.java.net/jeps/290">JEP 290: Filter Incoming Serialization Data</a>
</li>
</references>

</qhelp>
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import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter;
import org.springframework.remoting.rmi.RemoteInvocationSerializingExporter;

@Configuration
public class SpringExporterUnsafeDeserialization {

@Bean(name = "/unsafeHttpInvokerServiceExporter")
HttpInvokerServiceExporter unsafeHttpInvokerServiceExporter() {
HttpInvokerServiceExporter exporter = new HttpInvokerServiceExporter();
exporter.setService(new AccountServiceImpl());
exporter.setServiceInterface(AccountService.class);
return exporter;
}

@Bean(name = "/unsafeCustomeRemoteInvocationSerializingExporter")
RemoteInvocationSerializingExporter unsafeCustomeRemoteInvocationSerializingExporter() {
return new CustomeRemoteInvocationSerializingExporter();
}

HttpInvokerServiceExporter notABean() {
HttpInvokerServiceExporter exporter = new HttpInvokerServiceExporter();
exporter.setService(new AccountServiceImpl());
exporter.setServiceInterface(AccountService.class);
return exporter;
}
}

class CustomeRemoteInvocationSerializingExporter extends RemoteInvocationSerializingExporter {}

class NotAConfiguration {

@Bean(name = "/notAnEndpoint")
HttpInvokerServiceExporter notAnEndpoint() {
HttpInvokerServiceExporter exporter = new HttpInvokerServiceExporter();
exporter.setService(new AccountServiceImpl());
exporter.setServiceInterface(AccountService.class);
return exporter;
}
}

class AccountServiceImpl implements AccountService {

@Override
public String echo(String data) {
return data;
}
}

interface AccountService {
String echo(String data);
}
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| SpringExporterUnsafeDeserialization.java:10:32:10:63 | unsafeHttpInvokerServiceExporter | Unsafe deserialization in a Spring exporter bean '/unsafeHttpInvokerServiceExporter' |
| SpringExporterUnsafeDeserialization.java:18:41:18:88 | unsafeCustomeRemoteInvocationSerializingExporter | Unsafe deserialization in a Spring exporter bean '/unsafeCustomeRemoteInvocationSerializingExporter' |
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experimental/Security/CWE/CWE-502/UnsafeSpringExporterInConfigurationClass.ql
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| beans.xml:10:5:13:12 | /unsafeBooking | Unsafe deserialization in a Spring exporter bean '/unsafeBooking' |
| beans.xml:15:5:18:12 | org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter | Unsafe deserialization in a Spring exporter bean 'org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter' |
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experimental/Security/CWE/CWE-502/UnsafeSpringExporterInXMLConfiguration.ql
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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<bean id="anotherBookingService" class="com.gypsyengineer.server.CabBookingServiceImpl"/>

<bean name="/unsafeBooking" class="org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter">
<property name="service" ref="anotherBookingService"/>
<property name="serviceInterface" value="com.gypsyengineer.api.CabBookingService"/>
</bean>

<bean class="org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter">
<property name="service" ref="anotherBookingService"/>
<property name="serviceInterface" value="com.gypsyengineer.api.CabBookingService"/>
</bean>
</beans>
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//semmle-extractor-options: --javac-args -cp ${testdir}/../../../../stubs/springframework-5.2.3
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package org.springframework.context.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Target;

@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
public @interface Bean {

String[] name() default {};
}
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package org.springframework.context.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
public @interface Configuration {}
Original file line number Diff line number Diff line change
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package org.springframework.remoting.httpinvoker;

public class HttpInvokerServiceExporter extends org.springframework.remoting.rmi.RemoteInvocationSerializingExporter {

public void setService(Object service) {}

public void setServiceInterface(Class clazz) {}
}
Original file line number Diff line number Diff line change
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package org.springframework.remoting.rmi;

public abstract class RemoteInvocationSerializingExporter {}