hakivvi/cve-2022-29464Python exploit for CVE-2022-29464, an unauthenticated arbitrary file upload vulnerability in WSO2 servers, enabling remote code execution via malicious JSP file uploads.
WSO2 RCE (CVE-2022-29464) exploit and writeup.
CVE-2022-29464 is critical vulnerability on WSO2 discovered by Orange Tsai. the vulnerability is an unauthenticated unrestricted arbitrary file upload which allows unauthenticated attackers to gain RCE on WSO2 servers via uploading malicious JSP files.
the vulerable upload route is /fileupload which is handled by FileUploadServlet servlet. and it is unprotected route by IAM as we can see in the indentity.xml configuration file:
<Resource context="(.*)/fileupload(.*)" secured="false" http-method="all"/>
And also unprotected by the default login measure, handleSecurity() is the function responsible for securing the different routes served by WSO2 and provides a mechanism for performing security checks on the received HTTP requests, handleSecurity() will call CarbonUILoginUtil.handleLoginPageRequest() and based on its return value it will be decided to allow or deny access to the requested URI:
public boolean handleSecurity(HttpServletRequest request, HttpServletResponse response)
throws IOException {
[snipped]
if ((val = CarbonUILoginUtil.handleLoginPageRequest(requestedURI, request, response,
authenticated, context, indexPageURL)) != CarbonUILoginUtil.CONTINUE) {
if (val == CarbonUILoginUtil.RETURN_TRUE) {
return true;
} else {
return false;
}
}
[snipped]
}
CarbonUILoginUtil.handleLoginPageRequest() returns CarbonUILoginUtil.RETURN_TRUE when the route is /fileupload:
protected static int handleLoginPageRequest(String requestedURI, HttpServletRequest request,
HttpServletResponse response, boolean authenticated, String context, String indexPageURL)
throws IOException {
boolean isTryIt = requestedURI.indexOf("admin/jsp/WSRequestXSSproxy_ajaxprocessor.jsp") > -1;
boolean isFileDownload = requestedURI.endsWith("/filedownload");
if ((requestedURI.indexOf("login.jsp") > -1
|| requestedURI.indexOf("login_ajaxprocessor.jsp") > -1
|| requestedURI.indexOf("admin/layout/template.jsp") > -1
|| isFileDownload
|| requestedURI.endsWith("/fileupload")
|| requestedURI.indexOf("/fileupload/") > -1
|| requestedURI.indexOf("login_action.jsp") > -1
|| isTryIt
|| requestedURI.indexOf("tryit/JAXRSRequestXSSproxy_ajaxprocessor.jsp") > -1)
&& !requestedURI.contains(";")) {
if ((requestedURI.indexOf("login.jsp") > -1
|| requestedURI.indexOf("login_ajaxprocessor.jsp") > -1 || requestedURI
.indexOf("login_action.jsp") > -1) && authenticated) {
[snipped]
} else if ((isTryIt || isFileDownload) && !authenticated) {
[snipped]
} else if (requestedURI.indexOf("login_action.jsp") > -1 && !authenticated) {
[snipped]
} else {
if (log.isDebugEnabled()) {
log.debug("Skipping security checks for " + requestedURI);
}
return RETURN_TRUE;
}
}
return CONTINUE;
}
with CarbonUILoginUtil.handleLoginPageRequest() returning CarbonUILoginUtil.RETURN_TRUE, handleSecurity() will return true, the access will be then granted to /fileupload without authentication.
the FileUploadServlet servlet and upon init() and through a series of method calls loads eventually from the carbon.xml configuration file multiple upload file formats/actions along with the object which hanldes every format.
public void init(ServletConfig servletConfig) throws ServletException {
this.servletConfig = servletConfig;
try {
fileUploadExecutorManager = new FileUploadExecutorManager(bundleContext, configContext, webContext);
//Registering FileUploadExecutor Manager as an OSGi service
bundleContext.registerService(FileUploadExecutorManager.class.getName(), fileUploadExecutorManager, null);
} catch (CarbonException e) {
log.error("Exception occurred while trying to initialize FileUploadServlet", e);
throw new ServletException(e);
}
}
the FileUploadExecutorManager class constructor is as follows:
public FileUploadExecutorManager(BundleContext bundleContext,
ConfigurationContext configCtx,
String webContext) throws CarbonException {
this.bundleContext = bundleContext;
this.configContext = configCtx;
this.webContext = webContext;
this.loadExecutorMap();
}
the constructor calls the private method loadExecutorMap() which is where the configuration loading is done:
private void loadExecutorMap() throws CarbonException {
[snipped]
try {
documentElement = XMLUtils.toOM(serverConfiguration.getDocumentElement());
} catch (Exception e) {
String msg = "Unable to read Server Configuration.";
log.error(msg);
throw new CarbonException(msg, e);
}
[snipped]
OMElement fileUploadConfigElement =
documentElement.getFirstChildWithName(
new QName(ServerConstants.CARBON_SERVER_XML_NAMESPACE, "FileUploadConfig"));
for (Iterator iterator = fileUploadConfigElement.getChildElements(); iterator.hasNext();) {
OMElement mapppingElement = (OMElement) iterator.next();
if (mapppingElement.getLocalName().equalsIgnoreCase("Mapping")) {
OMElement actionsElement =
mapppingElement.getFirstChildWithName(
new QName(ServerConstants.CARBON_SERVER_XML_NAMESPACE, "Actions"));
String confPath = System.getProperty(CarbonBaseConstants.CARBON_CONFIG_DIR_PATH);
[snipped]
the file upload formats configurations is within the FileUploadConfig namespace in the XML configuration file, this is the default configuration:
<FileUploadConfig>
<!--
The total file upload size limit in MB
-->
<TotalFileSizeLimit>100</TotalFileSizeLimit>
<Mapping>
<Actions>
<Action>keystore</Action>
<Action>certificate</Action>
<Action>*</Action>
</Actions>
<Class>org.wso2.carbon.ui.transports.fileupload.AnyFileUploadExecutor</Class>
</Mapping>