转载

Some vulnerabilities in JEECMSV9

/src/main/java/com/jeecms/cms/action/member/UeditorAct.java

@RequestMapping(value = "/ueditor/getRemoteImage.jspx")
public void getRemoteImage(HttpServletRequest request,
		HttpServletResponse response) throws Exception {
	String url = request.getParameter("upfile");
	CmsSite site=CmsUtils.getSite(request);
	JSONObject json = new JSONObject();
	String[] arr = url.split(UE_SEPARATE_UE);
	String[] outSrc = new String[arr.length];
	for (int i = 0; i < arr.length; i++) {
		outSrc[i]=saveRemoteImage(arr[i], site.getContextPath(), site.getUploadPath());
	}
	String outstr = "";
	for (int i = 0; i < outSrc.length; i++) {
		outstr += outSrc[i] + UE_SEPARATE_UE;
	}
	outstr = outstr.substring(0, outstr.lastIndexOf(UE_SEPARATE_UE));
	json.put(URL, outstr);
	json.put(SRC_URL, url);
	json.put(TIP, LocalizedMessages.getRemoteImageSuccessSpecified(request));
	ResponseUtils.renderJson(response, json.toString());
}

在接受了用户传递过来的url之后, 带入saveRemoteImage方法

private String saveRemoteImage(String imgUrl,String contextPath,String uploadPath){
	HttpClientBuilder httpClientBuilder = HttpClientBuilder.create(); 
    CloseableHttpClient client = httpClientBuilder.build();  
	String outFileName="";
	try{
		if(endWithImg(imgUrl)){
			HttpGet httpget = new HttpGet(new URI(imgUrl));
			HttpResponse response = client.execute(httpget);
			InputStream is = null;
			OutputStream os = null;
			HttpEntity entity = null;
			entity = response.getEntity();
			is = entity.getContent();
			outFileName=UploadUtils.generateFilename(uploadPath, FileNameUtils.getFileSufix(imgUrl));
			os = new FileOutputStream(realPathResolver.get(outFileName));
			IOUtils.copy(is, os);
		}

在saveRemoteImage方法当中, 如果通过了endWithImg方法的检测,就直接发起请求, 并且把请求到的结果输出到文件当中。

private boolean endWithImg(String imgUrl){
	if(StringUtils.isNotBlank(imgUrl)&&(imgUrl.endsWith(".bmp")||imgUrl.endsWith(".gif")
			||imgUrl.endsWith(".jpeg")||imgUrl.endsWith(".jpg")
			||imgUrl.endsWith(".png"))){
			return true;
	}else{
		return false;
	}
}

endWithImg的检测比较简单, 绕过也比较简单加个?.jpg就可以绕过了。

不过本地测试时, 访问这个jpg文件的结果却是404.

首先来看看保存访问结果的文件的文件名生成方法, 是包含一个月份目录的。

public static String generateFilename(String path, String ext){
	return path + MONTH_FORMAT.format(new Date())
	+ RandomStringUtils.random(4, Num62.N36_CHARS) + "." + ext;
}

结果类似为 /u/cms/www/201902/15002619t400.jpg

而在jeecms的默认源码当中, 是不存在201902这个目录的。

并且在saveRemoteImage方法当中, 并没有”判断这个目录存不存在,如果不存在的话就创建该目录”这种逻辑。

在FileOutputStream时, 如果目录是不存在的话, 会出异常, 所以这里的文件并没有保存上。

要想保存上这个文件, 首先还是得创建这个目录。

在

@RequestMapping(value = "/ueditor/upload.jspx",method = RequestMethod.POST)
public void upload(
		@RequestParam(value = "Type", required = false) String typeStr,
		Boolean mark,
		HttpServletRequest request, HttpServletResponse response)
		throws Exception {
	responseInit(response);
	if (Utils.isEmpty(typeStr)) {
		typeStr = "File";
	}
	if(mark==null){
		mark=false;
	}
	JSONObject json = new JSONObject();
	JSONObject ob = validateUpload(request, typeStr);
	if (ob == null) {
		json = doUpload(request, typeStr, mark);
	} else {
		json = ob;
	}
	ResponseUtils.renderJson(response, json.toString());
}

直接查看调用的doUpload方法,

private JSONObject doUpload(HttpServletRequest request, String typeStr,Boolean mark)throws Exception {
    .......
    else {
					fileUrl = fileRepository.storeByExt(site.getUploadPath(),
							ext, uplFile);
				}

继续查看storeByExt方法

public String storeByExt(String path, String ext, MultipartFile file)
		throws IOException {
	//String filename = UploadUtils.generateFilename(path, ext);
	//File dest = new File(getRealPath(filename));
	String fileName=UploadUtils.generateRamdonFilename(ext);
	String fileUrl =path+fileName;
	File dest = new File(getRealPath(path),fileName);
	dest = UploadUtils.getUniqueFile(dest);
	store(file, dest);
	return fileUrl;
}

文件名和目录的生成方法和saveRemoteImage时使用的方法相同,然后调用了store方法。

private void store(MultipartFile file, File dest)throws IOException {
	try {
		UploadUtils.checkDirAndCreate(dest.getParentFile());
		file.transferTo(dest);
	} catch (IOException e) {
		log.error("Transfer file error when upload file", e);
		throw e;
	}
}

public static void checkDirAndCreate(File dir){
	if (!dir.exists())
		dir.mkdirs();
}

可以看到虽然在下载远程图片的功能中, 没有”如果不存在这个日期目录就创建该目录”这个逻辑, 但是在上传的时候存在这个逻辑。所以可以先通过上传, 创建了该目录之后, 再继续给SSRF利用。

上传这个功能, 需要登录之后才能正常使用。

因为在doupload方法之前,

JSONObject ob = validateUpload(request, typeStr);
		if (ob == null) {
			json = doUpload(request, typeStr, mark);
		} else {
			json = ob;
		}

经过了validateUpload方法, 在该方法当中

CmsUser user = CmsUtils.getUser(request);
// 非允许的后缀
if (!user.isAllowSuffix(ext)) {
	result.put(STATE, LocalizedMessages
			.getInvalidFileSuffixSpecified(request));
	return result;
}

如果是未登录状态, user为null 接下来就会出现空指针异常。

上传之后, 就成功创建了目录。

再SSRF

不过发起请求的httpClientBuilder, 仅支持HTTP/HTTPS协议。

SSTI

JEECMS中存在一些可以上传任意文件的点, 只举例一个

/src/main/java/com/jeecms/cms/action/member/SwfUploadAct.java

@RequestMapping(value = "/member/o_swfAttachsUpload.jspx", method = RequestMethod.POST)
public void swfAttachsUpload(
		String root,
		Integer uploadNum,
		@RequestParam(value = "Filedata", required = false) MultipartFile file,
		HttpServletRequest request, HttpServletResponse response,
		ModelMap model) throws Exception{
	super.swfAttachsUpload(root, uploadNum, file, request, response, model);
}

调用了父类的swfAttachsUpload方法,

protected void swfAttachsUpload(
		String root,
		Integer uploadNum,
		@RequestParam(value = "Filedata", required = false) MultipartFile file,
		HttpServletRequest request, HttpServletResponse response,
		ModelMap model) throws Exception {
	JSONObject data=new JSONObject();
	WebCoreErrors errors = validateUpload( file, request);
	if (errors.hasErrors()) {
		data.put("error", errors.getErrors().get(0));
		ResponseUtils.renderJson(response, data.toString());
	}else{
		CmsSite site = CmsUtils.getSite(request);
		String ctx = request.getContextPath();
		String origName = file.getOriginalFilename();
		String ext = FilenameUtils.getExtension(origName).toLowerCase(
				Locale.ENGLISH);
		// TODO 检查允许上传的后缀
		String fileUrl="";
		try {
			if (site.getConfig().getUploadToDb()) {
				String dbFilePath = site.getConfig().getDbFileUri();
				fileUrl = dbFileMng.storeByExt(site.getUploadPath(), ext, file
						.getInputStream());
				// 加上访问地址
				fileUrl = request.getContextPath() + dbFilePath + fileUrl;
			} else if (site.getUploadFtp() != null) {
				Ftp ftp = site.getUploadFtp();
				String ftpUrl = ftp.getUrl();
				fileUrl = ftp.storeByExt(site.getUploadPath(), ext, file
						.getInputStream());
				// 加上url前缀
				fileUrl = ftpUrl + fileUrl;
			}else if (site.getUploadOss() != null) {
				CmsOss oss = site.getUploadOss();
				fileUrl = oss.storeByExt(site.getUploadPath(), ext, file.getInputStream());
			} else {
				fileUrl = fileRepository.storeByExt(site.getUploadPath(), ext,
						file);
				// 加上部署路径
				fileUrl = ctx + fileUrl;
			}
			cmsUserMng.updateUploadSize(CmsUtils.getUserId(request), Integer.parseInt(String.valueOf(file.getSize()/1024)));
			fileMng.saveFileByPath(fileUrl, origName, false);
			model.addAttribute("attachmentPath", fileUrl);
		} catch (IllegalStateException e) {
			model.addAttribute("error", e.getMessage());
		} catch (IOException e) {
			model.addAttribute("error", e.getMessage());
		}
		data.put("attachUrl", fileUrl);
		data.put("attachName", origName);
		ResponseUtils.renderJson(response, data.toString());
	}
}

在这个方法中, 上传时没有检查文件的后缀,

从TODO注释中也能看出来, 检查允许上传的后缀这个功能还未实现就直接上线了。

不过在jeecms中上传的jsp,jspx文件并不能被访问到。

<servlet-mapping>
	<servlet-name>JeeCmsFront</servlet-name>
	<url-pattern>*.jspx</url-pattern>
</servlet-mapping>
<servlet-mapping>
	<servlet-name>JeeCmsFront</servlet-name>
	<url-pattern>*.jsp</url-pattern>
</servlet-mapping>

jsp和jspx文件都经过了JeeCmsFront,

<servlet>
	<servlet-name>JeeCmsFront</servlet-name>
	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
	<init-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>
			/WEB-INF/config/jeecms-servlet-front.xml
			/WEB-INF/config/plug/**/*-servlet-front-action.xml
		</param-value>
	</init-param>
	<load-on-startup>2</load-on-startup>
</servlet>

jsp和jspx文件都会经过org.springframework.web.servlet.DispatcherServlet, 上传上去的jsp文件肯定是没有对应的映射的就直接404了。

这里得结合一些其他的点进行利用,

/src/main/java/com/jeecms/cms/action/front/CsiCustomAct.java

@RequestMapping(value = "/csi_custom*.jspx")
public String custom(String tpl, HttpServletRequest request,
		HttpServletResponse response, ModelMap model) {
	log.debug("visit csi custom template: {}", tpl);
	CmsSite site = CmsUtils.getSite(request);
	if(StringUtils.isNotBlank(tpl)){
		// 将request中所有参数保存至model中。
		model.putAll(RequestUtils.getQueryParams(request));
		FrontUtils.frontData(request, model, site);
		FrontUtils.frontPageData(request, model);
		return FrontUtils.getTplPath(site.getSolutionPath(), TPLDIR_CSI_CUSTOM,
				tpl);
	}else{
		return FrontUtils.pageNotFound(request, response, model);
	}
}

可以看到将用户传递过来的tpl变量直接带入了getTplPath方法,

public static String getTplPath(String solution, String dir, String name){
	return solution + "/" + dir + "/" + name + TPL_SUFFIX;
}

可控的tpl变量直接拼接进了模板路径当中,

public static final String TPL_SUFFIX = ".html";

默认的模板后缀为.html, 高版本jdk当中已经不再能够截断, 所以这里先通过刚才的任意文件上传一个.html文件, 然后控制模板文件路径为自己上传的模板文件进行SSTI.

因为jeecms的模板引擎使用的是freemarker, 一开始以为直接用freemarker的SSTI就能rce了, 但是测试的时候失败了。

<#assignex="freemarker.template.utility.Execute"?new()> ${ ex("id") }

Some vulnerabilities in JEECMSV9

在新版本freemarker中, 多了一个TemplateClassResolver.SAFER_RESOLVER配置。

TemplateClassResolver.SAFER_RESOLVER now disallows creating freemarker.template.utility.JythonRuntime and freemarker.template.utility.Execute. This change affects the behavior of the new built-in if FreeMarker was configured to use SAFER_RESOLVER, which is not the default until 2.4 and is hence improbable.

TemplateClassResolver SAFER_RESOLVER = new TemplateClassResolver() {
    public Class resolve(String className, Environment env, Template template)throws TemplateException {
        if (!className.equals(ObjectConstructor.class.getName()) && !className.equals(Execute.class.getName()) && !className.equals("freemarker.template.utility.JythonRuntime")) {
            try {
                return ClassUtil.forName(className);
            } catch (ClassNotFoundException var5) {
                throw new _MiscTemplateException(var5, env);
            }
        } else {
            throw MessageUtil.newInstantiatingClassNotAllowedException(className, env);
        }
    }
}

如果使用了TemplateClassResolver.SAFER_RESOLVER, 就不允许再调用freemarker.template.utility.Execute, freemarker.template.utility.ObjectConstructor以及freemarker.template.utility.JythonRuntime。

public ConstructorFunction(String classname, Environment env, Template template)throws TemplateException {
            this.env = env;
            this.cl = env.getNewBuiltinClassResolver().resolve(classname, env, template);
            if (!TemplateModel.class.isAssignableFrom(this.cl)) {
                throw new _MiscTemplateException(NewBI.this, env, new Object[]{"Class ", this.cl.getName(), " does not implement freemarker.template.TemplateModel"});
            }

并且允许调用的类只允许为实现了freemarker.template.TemplateModel接口的类, 大概看了下实现了该接口的类, 除了不允许使用的三个类,没有找到其他能利用的类, 就只有放弃RCE了。

从文档中可以看出, freemarker从2.4版本以后才默认打开TemplateClassResolver.SAFER_RESOLVER, jeecms使用的版本为

<freemarker.version>2.3.25-incubating</freemarker.version>

虽然没有默认打开该配置, 但是JEECMS中的freemarker手动打开了TemplateClassResolver.SAFER_RESOLVER,所以SSTI没办法RCE了。

protected void initApplicationContext()throws BeansException {
	super.initApplicationContext();

	if (getConfiguration() == null) {
		FreeMarkerConfig config = autodetectConfiguration();
		Configuration configuration=config.getConfiguration();
		configuration.setNewBuiltinClassResolver(TemplateClassResolver.SAFER_RESOLVER);
		setConfiguration(configuration);
	}
	checkTemplate();
}

在TemplateClassResolver.SAFER_RESOLVER的限制下， SSTI也就只能读读文件了, 并且只能读取WEB目录下的文件。

Some vulnerabilities in JEECMSV9

反序列

JEECMS中使用了shiro, 版本为

<shiro.version>1.4.0</shiro.version>

老版本shiro(1.2.4)曾爆过一个反序列,

看了一下maven下载的1.4.0的shiro包, 依然存在反序列的点

protected PrincipalCollection convertBytesToPrincipals(byte[] bytes, SubjectContext subjectContext){
    if (this.getCipherService() != null) {
        bytes = this.decrypt(bytes);
    }

    return this.deserialize(bytes);
}

经过decrypt, aes解密之后就开始反序列了。

protected PrincipalCollection deserialize(byte[] serializedIdentity){
    return (PrincipalCollection)this.getSerializer().deserialize(serializedIdentity);
}

public T deserialize(byte[] serialized)throws SerializationException {
    if (serialized == null) {
        String msg = "argument cannot be null.";
        throw new IllegalArgumentException(msg);
    } else {
        ByteArrayInputStream bais = new ByteArrayInputStream(serialized);
        BufferedInputStream bis = new BufferedInputStream(bais);

        try {
            ObjectInputStream ois = new ClassResolvingObjectInputStream(bis);
            T deserialized = ois.readObject();
            ois.close();

高版本shiro只是没有在AbstractRememberMeManager中硬编码了AES的key, 但是在JEECMS当中, 又再次硬编码了AES的key

/src/main/webapp/WEB-INF/config/shiro-context.xml

<!-- rememberMe管理器 -->
<beanid="rememberMeManager"class="org.apache.shiro.web.mgt.CookieRememberMeManager">
    <propertyname="cipherKey"value="#{T(org.apache.shiro.codec.Base64).decode('4AvVhmFLUs0KTA3Kprsdag==')}"/>
    <propertyname="cookie"ref="rememberMeCookie"/>
</bean>

直接使用这个AES key就能打反序列了。

看了下JEECMS的jar包, 打反序列版本比较合适的为C3P0的jar包。

JEECMS的C3P0包版本和ysoserial自带的C3P0包版本相同。

<c3p0.version>0.9.5.2</c3p0.version>

一开始不知道C3P0这gadget到底是咋用, 看了下代码。

/com/mchange/c3p0/0.9.5.2/c3p0-0.9.5.2.jar!/com/mchange/v2/c3p0/impl/PoolBackedDataSourceBase.class

private void readObject(ObjectInputStream ois)throws IOException, ClassNotFoundException {
    short version = ois.readShort();
    switch(version) {
    case 1:
        Object o = ois.readObject();
        if (o instanceof IndirectlySerialized) {
            o = ((IndirectlySerialized)o).getObject();
        }

继续调用getObject方法

public Object getObject()throws ClassNotFoundException, IOException {
    try {
        InitialContext var1;
        if (this.env == null) {
            var1 = new InitialContext();
        } else {
            var1 = new InitialContext(this.env);
        }

        Context var2 = null;
        if (this.contextName != null) {
            var2 = (Context)var1.lookup(this.contextName);
        }

        return ReferenceableUtils.referenceToObject(this.reference, this.name, var2, this.env);

调用referenceToObject方法,

public static Object referenceToObject(Reference var0, Name var1, Context var2, Hashtable var3)throws NamingException {
    try {
        String var4 = var0.getFactoryClassName();
        String var11 = var0.getFactoryClassLocation();
        ClassLoader var6 = Thread.currentThread().getContextClassLoader();
        if (var6 == null) {
            var6 = ReferenceableUtils.class.getClassLoader();
        }

        Object var7;
        if (var11 == null) {
            var7 = var6;
        } else {
            URL var8 = new URL(var11);
            var7 = new URLClassLoader(new URL[]{var8}, var6);
        }

        Class var12 = Class.forName(var4, true, (ClassLoader)var7);
        ObjectFactory var9 = (ObjectFactory)var12.newInstance();
        return var9.getObjectInstance(var0, var1, var2, var3);

通过URLClassLoader获取远程jar包中的类, 然后classforname后, newInstance实例化该类，调用构造方法。

Some vulnerabilities in JEECMSV9

不过在打反序列的时候, 出现了suid错误

明明yso的C3P0版本和jeecms的一样, 但是还是提示suid错误。

因为jeecms中依赖了quartz-scheduler包, 这个包又依赖了0.9.1.1的c3p0. 反序列的时候调用的是老版本的C3P0的包。(这里我也不太懂我本地为什么调用的是老版本的包, 按理maven解决依赖冲突时优先最短路径优先, 应该调用的是0.9.5.2包。并且高版本的C3P0依赖在前,有大哥懂为啥调用老版本的jar包的麻烦教我一手。)

Some vulnerabilities in JEECMSV9