sni+tomcat漏洞复现

sni

SNI产生背景
SSL以及TLS（SSL的升级版）为客户端与服务器端进行安全连接提供了条件。但是，由于当时技术限制，SSL初期的设计顺应经典的公钥基础设施 PKI(Public Key Infrastructure)设计，PKI 认为一个服务器只为一个域名提供服务，从而一个服务器上也就只能使用一个证书。这样客户端在发送请求的时候，利用DNS域名解析，只要向解析到的IP地址（服务器地址）发送请求，然后服务器将自身唯一的证书返回回来，交给客户端验证，验证通过，则继续进行后续通信。然后通过协商好的加密通道，获得所需要的内容。这意味着服务器可以在 SSL 的启动动阶段发送或提交证书，因为它知道它在为哪个特定的域名服务。

随着HTTP 服务器开启虚拟主机支持后，每个服务器通过相同的IP地址可以为很多域名提供服务。这种为虚拟主机提供通信安全的简单途径，却经常导致使用了错误的数字证书，因为服务器端无法知道客户端到底请求的是哪个域名下的服务，从而导致浏览器对用户发出警告。

不幸的是，当设置了 SSL加密，服务器在读取HTTP请求里面的域名之前已经向客户端提交了证书，也就是已经为默认域提供了服务。但是，一个服务器可能为上千个域名提供服务，不可能将所有证书都发送给客户端，让客户端一一验证，找到与请求域名对应的证书。SNI的设计目的是为了让服务器根据请求来决定为哪个域服务，这个信息通常从HTTP请求头获得。

前置环境搭建：

[root@localhost nginx]# mkdir certificate
[root@localhost nginx]# cd certificate/[root@localhost certificate]# openssl genrsa -des3 -out ssl.key 4096 
[root@localhost certificate]# openssl req -new -key ssl.key -out aaa.csr
[root@localhost certificate]# openssl x509 -req -days 365 -in aaa.csr -signkey ssl.key  -out aaa.crt[root@localhost certificate]# openssl genrsa -des3 -out ssl2.key 4096 
[root@localhost certificate]# openssl req -new -key ssl2.key -out bbb.csr
[root@localhost certificate]# openssl x509 -req -days 365 -in bbb.csr -signkey ssl2.key -out bbb.crt

[root@localhost certificate]# cd /var/www/
[root@localhost www]# mkdir aaa
[root@localhost www]# mkdir bbb
[root@localhost www]# echo "this is a" > /var/www/aaa/index.html
[root@localhost www]# echo "this is b" > /var/www/bbb/index.html

修改本机hosts文件在C:\Windows\System32\drivers\etc下

单主机生效

双方使用同一个证书

server {listen       443 ssl;server_name  www.aaa.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/aaa;index  index.html index.htm;}}server {listen       443 ssl;server_name  www.bbb.com;ssl_certificate       /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/bbb;index  index.html index.htm;}}

双方使用不同证书

server {listen       443 ssl;server_name  www.aaa.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/aaa;index  index.html index.htm;}}server {listen       443 ssl;server_name  www.bbb.com;ssl_certificate      /usr/local/nginx/certificate/bbb.crt;ssl_certificate_key  /usr/local/nginx/certificate/sslb.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/bbb;index  index.html index.htm;}}

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证书与私钥的区分配置

server {listen       443 ssl;server_name  www.aaa.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/aaa;index  index.html index.htm;}}server {listen       443 ssl;server_name  www.bbb.com;ssl_certificate      /usr/local/nginx/certificate/bbb.crt;ssl_certificate_key  /usr/local/nginx/certificate/sslb.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/bbb;index  index.html index.htm;}}

端口号区分，证书区分

server {listen       8443 ssl;server_name  www.bbb.com;ssl_certificate      /usr/local/nginx/certificate/bbb.crt;ssl_certificate_key  /usr/local/nginx/certificate/sslb.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/bbb;index  index.html index.htm;}}server {listen       8444 ssl;server_name  www.aaa.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/aaa;index  index.html index.htm;}

端口号区分,证书不区分

server {listen       8443 ssl;server_name  www.bbb.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/bbb;index  index.html index.htm;}}server {listen       8444 ssl;server_name  www.aaa.com;ssl_certificate      /usr/local/nginx/certificate/aaa.crt;ssl_certificate_key  /usr/local/nginx/certificate/ssl.key;ssl_session_cache    shared:SSL:1m;ssl_session_timeout  5m;ssl_ciphers  HIGH:!aNULL:!MD5;ssl_prefer_server_ciphers  on;location / {root   /var/www/aaa;index  index.html index.htm;}

tomcat幽灵猫漏洞复现

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漏洞编号:
CVE-2020-1938
CNVD-2020-10487
影响版本：
Apache Tomcat = 6
7 <= Apache Tomcat < 7.0.100
8 <= Apache Tomcat < 8.5.51
9 <= Apache Tomcat < 9.0.31
解决措施：
配置ajp配置中的secretRequired跟secret属性来限制认证 ；
临时禁用AJP协议端口，在conf/server.xml配置文件中注释掉<Connector port=“8009” protocol="AJP/1.3"redirectPort=“8443” /> ；
环境搭建#

centos7安装git，如果有git则不用安装

yum install git -y

安装完成后使用下面的命令克隆环境

git clone https://github.com/laolisafe/CVE-2020-1938

启动Apache，注意有先安装java环境
java环境安装

wget https://download.oracle.com/java/19/latest/jdk-19_linux-x64_bin.tar.gztar -zxvf jdk-19_linux-x64_bin.tar.gz [root@localhost local]# tar -zxvf  /usr/local/jdk-19_linux-x64_bin.
tar (child): /usr/local/jdk-19_linux-x64_bin.：无法 open: 没有那个文件或目录
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now
如果在解压是出现这个问题就将压缩包移动到/home下[root@localhost local]# mv jdk-19_linux-x64_bin.tar.gz /home/
[root@localhost local]# cd /home/
[root@localhost home]# ls
jdk-19_linux-x64_bin.tar.gz  ztx
[root@localhost home]# tar -zxvf jdk-19_linux-x64_bin.tar.gz[root@localhost home]# vim /etc/profile
添加一下几行
JAVA_HOME=/usr/local/jdk19.0.2
JAVA_BIN=/usr/local/jdk19.0.2/bin
PATH=$PATH:$JAVA_BIN
CLASSPATH=$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME JAVA_BIN PATH CLASSPATH[root@localhost home]# source /etc/profile
[root@localhost home]# env 

tomcat环境安装

[root@localhost home]# wget https://dlcdn.apache.org/tomcat/tomcat-8/v8.5.85/bin/apache-tomcat-8.5.85.tar.gz
[root@localhost home]# tar -zxvf apache-tomcat-8.5.85.tar.gz[root@localhost home]# mv apache-tomcat-8.5.85/ /usr/local/tomcat8.0
[root@localhost home]# cd /usr/local/
[root@localhost local]#  ln -s /usr/local/tomcat8.0/ /usr/local/tomcat[root@localhost local]# cd tomcat8.0/bin/
[root@localhost bin]# ls
bootstrap.jar       commons-daemon-native.tar.gz  setclasspath.sh       tool-wrapper.bat
catalina.bat        configtest.bat                shutdown.bat          tool-wrapper.sh
catalina.sh         configtest.sh                 shutdown.sh           version.bat
catalina-tasks.xml  daemon.sh                     startup.bat           version.sh
ciphers.bat         digest.bat                    startup.sh
ciphers.sh          digest.sh                     tomcat-juli.jar
commons-daemon.jar  setclasspath.bat              tomcat-native.tar.gz
[root@localhost bin]# vim catalina.sh 
[root@localhost bin]# chmod +x *.sh
[root@localhost bin]# ./startup.sh （启动tomcat）

下载exp

git clone https://github.com/YDHCUI/CNVD-2020-10487-Tomcat-Ajp-lfi

我们这里读取WEB-INF/web.xml文件

python CNVD-2020-10487-Tomcat-Ajp-lfi.py -p 8009 -f WEB-INF/web.xml 192.168.221.130

解决方案#

1、临时禁用AJP协议端口，在conf/server.xml配置文件中注释掉
2、配置ajp配置中的secretRequired跟secret属性来限制认证
3、官方下载最新版