2022-29464 WSO2 API Manager 任意文件上传、远程代码执行漏洞-安全KER

漏洞描述

某些WSO2产品允许不受限制地上传文件，从而执行远程代码。以WSO2 API Manager 为例，它是一个完全开源的 API 管理平台。它支持API设计，API发布，生命周期管理，应用程序开发，API安全性，速率限制，查看API的统计信息，以及连接API，API产品和端点。

漏洞版本

WSO2 API Manager 2.2.0 及以上版本

WSO2 Identity Server 5.2.0 及以上

版本WSO2 Identity Server Analytics 5.4.0、5.4.1、5.5.0、5.6.0WSO2

Identity Server as Key Manager 5.3.0 及更高版本

WSO2 Enterprise Integrator 6.2.0 及更高版本

WSO2 Open Banking AM 1.4.0 及更高版本

WSO2 Open Banking KM 1.4.0 及更高

环境搭建

采用Dockerfile搭建 wso2/wso2am – Docker Image | Docker Hub

版本：WSO2 API Manager 4.0.0

# ————————————————————————

# Licensed under the Apache License, Version 2.0 (the “License”);

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an “AS IS” BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License

# ————————————————————————

# set base Docker image to AdoptOpenJDK CentOS Docker image

FROM adoptopenjdk/openjdk11:x86_64-centos-jdk-11.0.10_9

LABEL maintainer=”WSO2 Docker Maintainers <dev@wso2.org>” \

com.wso2.docker.source=”https://github.com/wso2/docker-apim/releases/tag/v4.0.0.1″

# set Docker image build arguments

# build arguments for user/group configurations

ARG USER=wso2carbon

ARG USER_ID=802

ARG USER_GROUP=wso2

ARG USER_GROUP_ID=802

ARG USER_HOME=/home/${USER}

# build arguments for WSO2 product installation

ARG WSO2_SERVER_NAME=wso2am

ARG WSO2_SERVER_VERSION=4.0.0

ARG WSO2_SERVER_REPOSITORY=product-apim

ARG WSO2_SERVER=${WSO2_SERVER_NAME}-${WSO2_SERVER_VERSION}

ARG WSO2_SERVER_HOME=${USER_HOME}/${WSO2_SERVER}

ARG WSO2_SERVER_DIST_URL=https://github.com/wso2/${WSO2_SERVER_REPOSITORY}/releases/download/v${WSO2_SERVER_VERSION}/${WSO2_SERVER}.zip

# build argument for MOTD

ARG MOTD=’printf “\n\

Welcome to WSO2 Docker resources.\n\

———————————— \n\

This Docker container comprises of a WSO2 product, running with its latest GA release \n\

which is under the Apache License, Version 2.0. \n\

Read more about Apache License, Version 2.0 here @ http://www.apache.org/licenses/LICENSE-2.0.\n\n”‘

# create the non-root user and group and set MOTD login message

RUN \

groupadd –system -g ${USER_GROUP_ID} ${USER_GROUP} \

&& useradd –system –create-home –home-dir ${USER_HOME} –no-log-init -g ${USER_GROUP_ID} -u ${USER_ID} ${USER} \

&& echo ${MOTD} > /etc/profile.d/motd.sh

# copy init script to user home

COPY –chown=wso2carbon:wso2 docker-entrypoint.sh ${USER_HOME}/

# install required packages

RUN \

yum -y update \

&& yum install -y \

nc \

unzip \

wget \

&& rm -rf /var/cache/yum/*

# add the WSO2 product distribution to user’s home directory

RUN \

wget -O ${WSO2_SERVER}.zip “${WSO2_SERVER_DIST_URL}” \

&& unzip -d ${USER_HOME} ${WSO2_SERVER}.zip \

&& chown wso2carbon:wso2 -R ${WSO2_SERVER_HOME} \

&& mkdir ${USER_HOME}/wso2-tmp \

&& bash -c ‘mkdir -p ${USER_HOME}/solr/{indexed-data,database}’ \

&& chown wso2carbon:wso2 -R ${USER_HOME}/solr \

&& cp -r ${WSO2_SERVER_HOME}/repository/deployment/server/synapse-configs ${USER_HOME}/wso2-tmp \

&& cp -r ${WSO2_SERVER_HOME}/repository/deployment/server/executionplans ${USER_HOME}/wso2-tmp \

&& rm -f ${WSO2_SERVER}.zip

# set the user and work directory

USER ${USER_ID}

WORKDIR ${USER_HOME}

# set environment variables

ENV WORKING_DIRECTORY=${USER_HOME} \

WSO2_SERVER_HOME=${WSO2_SERVER_HOME}

# expose ports

EXPOSE 9763 9443 9999 11111 8280 8243 5672 9711 9611 9099

# initiate container and start WSO2 Carbon server

ENTRYPOINT [“/home/wso2carbon/docker-entrypoint.sh”]

运行docker run命令搭建docker环境。

docker run -it -p 8280:8280 -p 8243:8243 -p 9443:9443 –name api-manager wso2/wso2am:4.0.0

搭建完成后，访问 https://localhost:9943 默认用户名密码 admin admin。

漏洞复现

漏洞原理

补丁diff记录（https://github.com/wso2/carbon-kernel/pull/3152/commits/13795df0a5b6a2206fd0338abfff057a7b99e1bb）Remove Unnecessary file uploader classes and improve parent path validation. by bhagyasakalanka · Pull Request #3152 · wso2/carbon-kernel (github.com)

查看diff记录、在创建file对象时会先对上传文件的路径做校验。

carbon-kernel/FileUploadServlet.java at 4.4.x · wso2/carbon-kernel (github.com)

开启docker镜像调试模式，在idea上使用远程调试。

docker run -it -p 8280:8280 -p 8243:8243 -p 9443:9443 -p 5005:5005 –name another-api-manager wso2/wso2am:4.0.0 -debug *:5005

/fileupload 会在服务器启动期间被注册。

在使用文件上传时，会调用/org/wso2/carbon/ui/transports/FileUploadServlet.java 。

构造函数FileUploadServlet 会将类内部定义的私有属性进行修改。

使用POST方法时，会调用doPost(),接着调用fileUploadExecutorManager.execute()

因此我们将断点打到/org/wso2/carbon/ui/transports/fileupload/FileUploadExecutorManager.java#execute，正如上面描述所说、当收到一个文件上传请求，这个方法会被调用。它接受的两个参数：http request、https response，会返回布尔值。

CarbonConstants类包含Carbon所有重要常数

然后对CarbonConstants的cookie、webContext、SERVER_URL、进行操作。向下走，通过对requestURI的截取获得actionString。

在下面的代码中会注册execution handlers、首先会创建execHandlerManager对象，接下来会加上ExecHandler链条。FileUploadExecutionHandlerManager => CarbonXmlFileUploadExecHandler=>OSGiFileUploadExecHandler=>AnyFileUploadExecHandler。