Tactics, Techniques, and Procedures
Personal BlogTwitterGitHubContact
  • Tactics, Techniques, and Procedures
  • ☠️Pentesting
    • Fortress
      • Automation
      • Cisco
        • Cisco Adaptive Security Appliance
        • Cisco Smart Install
      • CMS
        • Drupal
        • Wordpress
      • Exchange
      • Office365
      • Okta
      • Outlook Web Access (OWA)
      • SSH
      • Subdomain Takeover
    • Infrastructure
      • Active Directory
        • AD CS
        • Coercing Authentication
        • Credential Dumping
          • Cached Domain Credentials
          • Data Protection API (DPAPI)
          • Group Policy Preferences
          • LSA Secrets
          • LSASS Memory
          • NTDS
          • Security Account Manager (SAM)
          • Kerberos Tickets
          • Unsecured Credentials
          • WDigest
          • WiFi Profiles
        • Delegation Abuse
          • Constrained Delegation
          • Unconstrained Delegation
        • Domain Enumeration
        • Domain Dominance
          • Forge Golden Ticket
          • Forge Silver Ticket
          • Forge Trust Ticket
          • Skeleton Key
        • Group Policy Preferences
        • Kerberos
          • AS-REP Roasting
          • Kerberoasting
          • Kerberos Relaying
        • Lateral Movement
          • PowerShell
          • Windows Remote Management (WinRM)
        • Local Administrator Password Solution (LAPS)
        • NoPac
        • NTLMv1
        • Password Cracking
        • Password Policy
        • Password Spraying
        • Reconnaissance
        • Relaying
          • LDAP Relaying
          • SMB Relaying
        • Shadow Credentials
        • Zerologon
      • Database Management System (DBMS)
        • Microsoft SQL Server
      • Defense Evasion
        • Disable or Modify Tools
        • Disable Windows Event Logging
        • Impair Command History Logging
        • Timestomping
      • Low-Hanging Fruit
      • Networks
        • IPv6
        • LLMNR/NBT-NS Poisoning
        • Network Scanning
        • Network Sniffing
        • Segmentation Testing
        • Simple Network Management Protocol (SNMP)
        • Subnet Enumeration
        • Identifying Domain Information
      • Persistence
        • Create Account
        • Remote Desktop
        • Services
          • Service Privilege Escalation / Persistence
          • Systemd Service Persistence
        • Web Shell
        • DLL Hijacking
      • Pivoting
      • Privilege Escalation
        • Linux
          • Setuid and Setgid
        • Windows
          • Privilege Abuse
            • SeImpersonatePrivilege
            • SeLoadDriverPrivilege
          • Service Exploitation
    • Initial Access
      • Phishing
        • Creating Templates
          • Leveraging AI During Template Creation
        • Payloads
          • Non-malicious Callback
          • Macros
    • OSINT
      • Identifying Users
      • Network Information
      • Search Engines
    • Web Applications
      • Access Control
      • APIs
        • Swagger API
      • Authentication
        • Account Takeover
      • Clickjacking
      • Cross Origin Resource Sharing (CORS)
      • Cross Site Request Forgery (CSRF)
      • Document Object Model (DOM)
      • File Upload
      • Google Dorking
      • GraphQL
      • HTTP Request Smuggling
      • Information Disclosure
      • Insecure Direct Object Reference (IDOR)
      • Injection Vulnerabilities
        • Cross-Site Scripting (XSS)
          • Blind Cross-Site Scripting
          • Finding Cross-Site Scripting
          • Stealing Cookies
          • XSS Payloads
        • CSV Injection
        • XML External Entity Injection (XXE)
        • LDAP Injection
        • NoSQL Injection
        • Server-Side Template Injection
        • SQL Injection
      • JSON Web Tokens (JWT)
      • Local File Inclusion (LFI)
      • OAuth
      • Open Redirection
      • Password Reset Poisoning
      • Prototype Pollution
      • Race Condition
      • Rate Limit Bypass
      • Remote Code Execution (RCE)
      • Remote File Inclusion (RFI)
      • Suspicious Parameters
      • Tooling
        • Burp Suite
          • Authentication / Proxy Issues
          • Intruder Attack Types
          • Match and Replace
          • Quality of Life
        • Misc Tooling
      • WAF Bypasses
      • WebSockets
      • Web Cache Deception
      • Web Cache Poisoning
    • Wireless
      • WPA / WPA2
        • Alfa Troubleshooting
        • Enterprise
        • Personal
    • Cloud
      • Amazon Web Services (AWS)
      • Microsoft Azure
  • 🧨Red Teaming
    • C2
      • Cobalt Strike
      • Empire
      • Metasploit
        • Metasploit Datatabase
      • Mythic
      • Sliver
    • Malware Dev
    • Offensive Infrastructure
      • Cloud Fronting
      • Redirectors
      • OpSec
      • Phishing Infrastructure
      • Creating a Dropbox
    • Offensive Tactics
    • Philosophy
  • 🦋Bug Bounty
    • Bug Bounty Tips & Tricks
  • 📖Resources
    • Blog Posts and Goodies
    • Checklists
    • Offensive Security Notes
    • Tooling Repository
    • Active Directory Toolkit
Powered by GitBook
On this page
  • Description
  • Attacking JWTs
  • References
  1. Pentesting
  2. Web Applications

JSON Web Tokens (JWT)

PreviousSQL InjectionNextLocal File Inclusion (LFI)

Last updated 2 years ago

Description

JSON Web Token (JWT) is an open standard () that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with the HMAC algorithm) or a public/private key pair using RSA or ECDSA.

Attacking JWTs

JWT_Tool

One of the most common and thorough tools to attack JWT is .

None Alg

As the JWT header can be tampered with client-side, a malicious user could change the "alg" header to "none", then remove the signature and check whether the server still accepts the token.

If it does, they could exploit this vulnerability by supplying an arbitrary claim in the JWT payload to escalate their privileges or impersonate other users. For example, if the token contains a "username": "joe" claim, they could change this to "username": "admin".

Brute-force Secret Keys

Some signing algorithms, such as HS256 (HMAC + SHA-256), use an arbitrary, standalone string as the secret key. Just like a password, it's crucial that this secret can't be easily guessed or brute-forced by an attacker. Otherwise, they may be able to create JWTs with any header and payload values they like, then use the key to re-sign the token with a valid signature.

JWT Header Parameter Injections

JWK

The JSON Web Signature (JWS) specification describes an optional jwk header parameter, which servers can use to embed their public key directly within the token itself in JWK format.

If the server does not whitelist specific public keys, we can supply an arbitrary key.

KID

Servers may use several cryptographic keys for signing different kinds of data, not just JWTs. For this reason, the header of a JWT may contain a kid (Key ID) parameter, which helps the server identify which key to use when verifying the signature.

References

If this parameter is also vulnerable to , an attacker could potentially force the server to use an arbitrary file from its filesystem as the verification key.

If the server stores its verification keys in a database, the kid header parameter is also a potential vector for attacks.

☠️
RFC 7519
jwt_tool
directory traversal
SQL injection
LogoJWT.IO - JSON Web Tokens Introduction