06 Mar, 2023

Insecure Token Generation

Vulnerability Assessment as a Service (VAaaS)

Tests systems and applications for vulnerabilities to address weaknesses.

Insecure Token Generation refers to the practice of creating access tokens in a way that leaves them vulnerable to exploitation by malicious actors. Access tokens are used to authenticate users and grant them access to protected resources or services. If these tokens are generated in an insecure manner, they can be easily intercepted or manipulated, allowing unauthorized access to sensitive data.

Insecure token generation can occur due to various reasons, such as using weak cryptographic algorithms, using predictable or easily guessable token values, failing to encrypt or hash the tokens, or transmitting them over insecure channels. These vulnerabilities can be exploited through attacks such as token replay attacks, session hijacking, and impersonation attacks.

Example of vulnerable code on different programming languages:


in Python:

				
					import random
import string

# Generate access token with weak entropy
def generate_access_token():
    return ''.join(random.choices(string.ascii_uppercase + string.digits, k=6))

# Example usage
access_token = generate_access_token()

				
			


In this Python example, the generate_access_token() function uses the random.choices() method to generate a six-character access token from a limited set of uppercase letters and digits. This token has weak entropy, making it susceptible to guessing and brute-force attacks.

• in PHP:

				
					// Generate access token using a weak algorithm
function generate_access_token() {
    $time = time();
    $token = md5($time);
    return $token;
}

// Example usage
$access_token = generate_access_token();

				
			


In this PHP example, the generate_access_token() function generates an access token using the MD5 hash of the current Unix timestamp. This token is vulnerable to collision attacks and can be easily predicted, making it insecure.

• in Java:

				
					import java.util.Random;

// Generate access token using a predictable seed value
public class TokenGenerator {
    private static final Random RANDOM = new Random(12345L);

    public static String generateAccessToken(int length) {
        byte[] bytes = new byte[length];
        RANDOM.nextBytes(bytes);
        return new String(bytes);
    }
}

// Example usage
String access_token = TokenGenerator.generateAccessToken(8);

				
			


In this Java example, the TokenGenerator class generates an access token using a Random object with a fixed seed value. This makes the token predictable and susceptible to attacks.

Examples of exploitation Insecure Token Generation

Token Replay Attack:

In this attack, an attacker intercepts a valid access token and reuses it to gain unauthorized access to a protected resource or service. This can occur if the token is generated using weak cryptographic algorithms or if it is transmitted over an insecure channel.

Session Hijacking:

In this attack, an attacker steals a valid access token or session identifier to gain unauthorized access to a user’s session. This can occur if the token is generated using predictable or easily guessable values or if it is transmitted over an insecure channel.

Impersonation Attack:

In this attack, an attacker creates a valid access token or session identifier to impersonate a legitimate user and gain access to a protected resource or service. This can occur if the token is generated using weak cryptographic algorithms or if it is transmitted over an insecure channel.

Privilege escalation techniques for Insecure Token Generation

Token Manipulation:

An attacker can modify an access token to gain elevated privileges. For example, an attacker can change the access level of a token from “user” to “admin” to gain administrative privileges.

Session Fixation:

An attacker can force a victim to use a specific access token or session identifier that the attacker controls. This can occur if the application uses predictable or easily guessable values for session identifiers or if the tokens are transmitted over an insecure channel.

Token Prediction:

An attacker can predict the value of an access token by analyzing patterns in the token generation process or by using brute-force techniques. This can occur if the tokens are generated using weak cryptographic algorithms or if they have insufficient entropy.

General methodology and checklist for Insecure Token Generation

Methodology:

  1. Identify where access tokens are generated: Determine the parts of the application that generate access tokens and the technologies and frameworks used.

  2. Identify how access tokens are generated: Review the code or configuration used to generate access tokens, including any libraries or functions used.

  3. Test token strength and predictability: Use tools like Burp Suite or OWASP ZAP to test the strength and predictability of access tokens. This can involve analyzing the entropy of the tokens, attempting to predict the values of the tokens, and testing for token reuse or replay attacks.

  4. Test token transmission: Test the transmission of access tokens between the client and server, including any use of encryption or secure channels. This can involve analyzing network traffic, testing for token leakage or exposure, and testing for man-in-the-middle attacks.

  5. Test token storage: Test the storage of access tokens on the client and server, including any use of encryption or hashing. This can involve analyzing cookies or other storage mechanisms, testing for token tampering or manipulation, and testing for session fixation or hijacking.

  6. Test for privilege escalation: Test for privilege escalation vulnerabilities, including token manipulation, session fixation, and token prediction attacks.

  7. Remediate vulnerabilities: Address any vulnerabilities identified through testing, including improving token generation processes, implementing secure token transmission and storage mechanisms, and addressing any privilege escalation vulnerabilities.

Checklist:

  1. Review the application code or configuration files to identify where access tokens are generated and how they are used.

  2. Test the strength and predictability of access tokens by analyzing their entropy and attempting to predict their values using tools like Burp Suite or OWASP ZAP.

  3. Test the transmission of access tokens between the client and server, including any use of encryption or secure channels, to identify vulnerabilities like token leakage or exposure.

  4. Test the storage of access tokens on the client and server, including any use of encryption or hashing, to identify vulnerabilities like token tampering or manipulation.

  5. Test for privilege escalation vulnerabilities like token manipulation, session fixation, and token prediction attacks.

  6. Verify that access tokens are invalidated or revoked when a user logs out or when the token expires.

  7. Verify that access tokens are not reused or replayed to gain unauthorized access to protected resources or services.

  8. Verify that access tokens are generated using secure cryptographic algorithms and that they have sufficient entropy to prevent brute-force attacks.

  9. Verify that access tokens are transmitted and stored securely, using encryption or hashing as appropriate, to prevent unauthorized access or tampering.

  10. Address any vulnerabilities identified through testing, including improving token generation processes, implementing secure token transmission and storage mechanisms, and addressing any privilege escalation vulnerabilities.

Tools set for exploiting Insecure Token Generation

Manual Tools:

  • Burp Suite: A web application security testing tool that includes features for analyzing access tokens and testing for vulnerabilities like token leakage or exposure, token reuse, and session fixation.

  • OWASP ZAP: An open-source web application security scanner that includes features for testing access token strength and predictability, as well as identifying vulnerabilities like session hijacking and token tampering.

  • Fiddler: A web debugging proxy that can be used to analyze network traffic and test for vulnerabilities like token leakage or exposure, as well as to modify and replay requests to test for privilege escalation vulnerabilities.

  • Wireshark: A network protocol analyzer that can be used to capture and analyze network traffic, including access token transmission, to identify vulnerabilities like man-in-the-middle attacks or token exposure.

  • cURL: A command-line tool for transferring data using various protocols, including HTTP and HTTPS, that can be used to test access token transmission and storage vulnerabilities.

  • Chrome Developer Tools: A set of tools built into the Chrome browser that can be used to analyze web page resources, including cookies and access tokens, to identify vulnerabilities like token exposure or leakage.

  • Firefox Developer Tools: A set of tools built into the Firefox browser that can be used to analyze web page resources, including cookies and access tokens, to identify vulnerabilities like token exposure or leakage.

  • SQLMap: An automated tool for testing SQL injection vulnerabilities that can be used to identify vulnerabilities in access token generation and storage processes.

  • Hydra: An automated tool for brute-forcing login credentials that can be adapted to test for vulnerabilities in access token generation and storage processes.

  • Nmap: A network exploration and security auditing tool that can be used to identify open ports and services, as well as to scan for vulnerabilities like token exposure or leakage.

Automated Tools:

  • Netsparker: An automated web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Acunetix: An automated web application security scanner that includes features for testing access token strength and predictability, as well as for identifying vulnerabilities like session fixation and token tampering.

  • Qualys: A cloud-based vulnerability management platform that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Nessus: A network vulnerability scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • AppScan: An automated web application security scanner that includes features for testing access token strength and predictability, as well as for identifying vulnerabilities like session fixation and token tampering.

  • WebInspect: An automated web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Wapiti: An open-source web application vulnerability scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Skipfish: An automated web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Vega: An open-source web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Arachni: An open-source web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • IronWASP: An open-source web application security scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • Metasploit: An open-source framework for developing and executing exploit code, including exploits for vulnerabilities in access token generation and storage processes.

  • BeEF: An open-source browser exploitation framework that can be used to test for vulnerabilities like session fixation or token tampering, as well as for testing access token transmission and privilege escalation vulnerabilities.

  • XSStrike: An open-source cross-site scripting (XSS) scanner that includes features for identifying vulnerabilities in access token generation and storage processes, as well as for testing access token transmission and privilege escalation vulnerabilities.

Browser Plugins:

  • Tamper Data: A Firefox browser plugin that can be used to intercept and modify HTTP requests, including requests that transmit access tokens, to test for vulnerabilities like token tampering or privilege escalation.

  • Cookie Manager+: A Chrome browser plugin that can be used to manage and manipulate cookies, including access tokens, to test for vulnerabilities like token tampering or privilege escalation.

  • Web Developer: A browser plugin for Chrome and Firefox that includes features for analyzing and modifying web page resources, including access tokens, to test for vulnerabilities like token exposure or leakage.

  • HackBar: A browser plugin for Firefox that includes features for testing web application security, including testing for vulnerabilities in access token generation and storage processes.

  • Cookie Editor: A browser plugin for Chrome and Firefox that can be used to manage and manipulate cookies, including access tokens, to test for vulnerabilities like token tampering or privilege escalation.

Average CVSS score of stack Insecure Token Generation

The CVSS (Common Vulnerability Scoring System) score for vulnerabilities related to insecure token generation can vary depending on the specific circumstances of the vulnerability. However, the CVSS score for this type of vulnerability is typically high to critical, as an attacker who is able to exploit this vulnerability can gain access to sensitive data or functionality, elevate their privileges, or carry out other types of attacks.

The CVSS score is based on a variety of factors, including the complexity of the attack, the level of privileges required to exploit the vulnerability, and the impact that the vulnerability can have on the system or application. Because of the potentially serious impact of insecure token generation vulnerabilities, they are often assigned a CVSS score of 7.0 or higher, indicating a high level of severity.

It is important to note, however, that the specific CVSS score for any given vulnerability will depend on the unique circumstances of that vulnerability, and should be evaluated on a case-by-case basis. Additionally, the CVSS score is only one factor that should be considered when evaluating the severity of a vulnerability, and should be used in conjunction with other factors such as the likelihood of the vulnerability being exploited and the potential impact of an exploit.

The Common Weakness Enumeration (CWE)

• CWE-334: Small Space of Random Values: This category covers situations where the generation of random tokens or values is not sufficiently random, leading to a small or predictable range of possible values that can be easily guessed or brute-forced.

• CWE-327: Use of a Broken or Risky Cryptographic Algorithm: This category covers situations where insecure cryptographic algorithms or methods are used to generate or process access tokens, making them vulnerable to attacks such as brute-forcing or cryptographic attacks.

• CWE-520: Incomplete or Partially Trusted Data: This category covers situations where access tokens are generated or processed using incomplete or partially trusted data sources, such as user input or external APIs, which can lead to vulnerabilities such as injection attacks or token tampering.

• CWE-319: Cleartext Transmission of Sensitive Information: This category covers situations where access tokens are transmitted in cleartext over insecure channels such as HTTP, making them vulnerable to interception or theft.

• CWE-250: Execution with Unnecessary Privileges: This category covers situations where access tokens are granted excessive or unnecessary privileges, leading to privilege escalation vulnerabilities or other types of attacks.

• CWE-259: Use of Hard-coded Credentials: This category covers situations where access tokens or other authentication credentials are hard-coded into the application code, making them vulnerable to theft or abuse by attackers.

• CWE-346: Origin Validation Error: This category covers situations where access tokens are not properly validated or checked for authenticity, leading to vulnerabilities such as replay attacks or token substitution.

• CWE-602: Client-side Enforcement of Server-side Security: This category covers situations where access tokens or other security mechanisms are enforced on the client side, rather than on the server side, making them vulnerable to bypass or tampering.

• CWE-309: Use of Password System for Primary Authentication: This category covers situations where access tokens or other authentication mechanisms are based on weak or easily guessable passwords, leading to vulnerabilities such as brute-forcing or dictionary attacks.

• CWE-285: Improper Authorization: This category covers situations where access tokens are not properly authorized or authenticated, leading to vulnerabilities such as privilege escalation or unauthorized access to sensitive data or functionality.

CVES related to Insecure Token Generation

CVE-2022-45782 – An issue was discovered in dotCMS core 5.3.8.5 through 5.3.8.15 and 21.03 through 22.10.1. A cryptographically insecure random generation algorithm for password-reset token generation leads to account takeover.

CVE-2022-26779 – Apache CloudStack prior to 4.16.1.0 used insecure random number generation for project invitation tokens. If a project invite is created based only on an email address, a random token is generated. An attacker with knowledge of the project ID and the fact that the invite is sent, could generate time deterministic tokens and brute force attempt to use them prior to the legitimate receiver accepting the invite. This feature is not enabled by default, the attacker is required to know or guess the project ID for the invite in addition to the invitation token, and the attacker would need to be an existing authorized user of CloudStack.

CVE-2018-14709 – Incorrect access control in the Dashboard API on Drobo 5N2 NAS version 4.0.5-13.28.96115 allows attackers to bypass authentication due to insecure token generation.

Insecure Token Generation exploits

  • Session hijacking: An attacker can steal an access token used for session management, allowing them to take over a user’s session without needing to authenticate themselves.

  • Token substitution: An attacker can substitute their own access token for a legitimate token, granting them unauthorized access to a user’s data or functionality.

  • Token tampering: An attacker can modify an access token to grant themselves additional privileges or access to sensitive data.

  • Brute-force attacks: An attacker can use a brute-force attack to guess or generate access tokens, potentially allowing them to bypass authentication mechanisms and gain unauthorized access to sensitive data or functionality.

  • Cross-site scripting (XSS): An attacker can inject malicious code into a web page or application, potentially allowing them to steal access tokens or carry out other types of attacks.

  • Cross-site request forgery (CSRF): An attacker can use a CSRF attack to force a user’s browser to perform actions on their behalf, potentially allowing them to use the user’s access token to carry out unauthorized actions.

  • Man-in-the-middle (MITM) attacks: An attacker can intercept traffic between a user and a server, potentially allowing them to steal access tokens or modify them in transit.

  • Token replay attacks: An attacker can intercept and replay a valid access token, potentially allowing them to gain unauthorized access to sensitive data or functionality.

  • Token leakage: An attacker can obtain access tokens through a vulnerability in the application or system, potentially allowing them to gain unauthorized access to sensitive data or functionality.

  • Privilege escalation: An attacker can use an insecurely generated access token to escalate their privileges, potentially allowing them to gain unauthorized access to sensitive data or functionality.

Practicing in test for Insecure Token Generation

Build a test application: Create a test application that includes access token generation and management, and deliberately introduce vulnerabilities such as weak or predictable token generation, token leakage, or insufficient token validation.

Use a vulnerable application: Use a known vulnerable application that has insecure token generation and management, and practice exploiting the vulnerabilities using various tools and techniques.

Practice with Capture the Flag (CTF) challenges: Participate in CTF challenges that involve exploiting insecure token generation vulnerabilities, such as guessing or brute-forcing tokens, stealing tokens through XSS or CSRF attacks, or manipulating tokens to gain unauthorized access.

Use online labs: Use online labs that provide virtual environments for practicing testing and exploiting vulnerabilities, including insecure token generation.

Participate in bug bounty programs: Participate in bug bounty programs that allow you to find and report vulnerabilities in real-world applications, including those related to insecure token generation.

Attend training or workshops: Attend training sessions or workshops that cover the fundamentals of testing for insecure token generation, as well as the latest tools and techniques for identifying and exploiting vulnerabilities.

For study Insecure Token Generation

Learn the basics of access tokens: Start by understanding what access tokens are and how they are used in different applications and systems. Learn about the different types of access tokens, including session tokens, JWTs, and OAuth tokens.

Study common vulnerabilities: Familiarize yourself with the common vulnerabilities associated with insecure token generation, such as weak or predictable token generation, token leakage, and insufficient token validation.

Practice testing techniques: Learn about the different tools and techniques for testing for insecure token generation, including manual testing, automated testing, and vulnerability scanning.

Learn to exploit vulnerabilities: Understand how attackers can exploit vulnerabilities in insecure token generation to gain unauthorized access to sensitive data or functionality. Practice exploiting vulnerabilities using various tools and techniques.

Stay up to date with the latest threats and countermeasures: Stay informed about the latest threats and countermeasures related to insecure token generation. Follow security blogs and news sites, attend training sessions or workshops, and participate in bug bounty programs to stay up to date with the latest developments.

Practice regularly: Make sure to practice regularly to keep your skills sharp and stay up to date with the latest techniques and tools. Look for opportunities to practice testing and exploiting vulnerabilities in real-world applications and systems.

Books with review of Insecure Token Generation

OAuth 2.0: Getting Started in Web-API Security by Matthias Biehl – This book provides a detailed introduction to OAuth 2.0, including how to generate and manage access tokens securely.

The Web Application Hacker’s Handbook: Finding and Exploiting Security Flaws by Dafydd Stuttard and Marcus Pinto – This book covers a wide range of web application security topics, including insecure token generation.

Web Security for Developers: Real Threats, Practical Defense by Malcolm McDonald – This book provides a practical guide to web security for developers, including how to secure access tokens and prevent token-related vulnerabilities.

Hacking Web Apps: Detecting and Preventing Web Application Security Problems by Mike Shema – This book covers a range of web application security topics, including session and token management.

Mastering OAuth 2.0: Create Secure APIs and Securely Integrate with External Apps by Charles Bihis – This book provides a comprehensive guide to OAuth 2.0, including how to generate and manage secure access tokens.

The Basics of Web Hacking: Tools and Techniques to Attack the Web by Josh Pauli – This book covers the basics of web hacking, including how to exploit vulnerabilities related to token generation and management.

OAuth 2.0 Identity and Access Management Patterns: Implementing OAuth 2.0 Patterns for Secure Authorization and Authentication by Prabath Siriwardena – This book covers a range of OAuth 2.0 patterns, including how to securely generate and manage access tokens.

Real-World Bug Hunting: A Field Guide to Web Hacking by Peter Yaworski – This book provides a practical guide to web hacking, including how to identify and exploit vulnerabilities related to token management.

OWASP Testing Guide v4 – This guide provides detailed information on how to test web applications for vulnerabilities, including insecure token generation.

Securing Web Applications: Security Design Patterns and Best Practices by Brian Glas and Daniel Kligerman – This book provides a comprehensive guide to securing web applications, including how to secure access tokens and prevent token-related vulnerabilities.

List of payloads Insecure Token Generation

  • Predictable tokens: Generate a list of predictable token values and attempt to use them to access protected resources.

  • Token tampering: Modify token values to attempt to gain unauthorized access or privileges.

  • Token injection: Inject malicious code into token values to exploit vulnerabilities in the application or system.

  • Token flooding: Generate a large number of tokens to overload the system and cause a denial-of-service (DoS) attack.

  • Token revocation: Attempt to revoke tokens by sending a request with a fake or expired token.

  • Token exhaustion: Generate a large number of tokens to exhaust the system’s resources and cause a DoS attack.

  • Token hijacking: Attempt to steal tokens by intercepting them in transit or using social engineering techniques to trick users into providing their tokens.

  • Token impersonation: Attempt to impersonate other users by modifying token values or stealing their tokens.

  • Token reuse: Attempt to reuse tokens that have already been used to gain unauthorized access to protected resources.

  • Token disclosure: Attempt to extract sensitive information from token values, such as user names, passwords, or other credentials.

How to be protected from Insecure Token Generation

  1. Use a secure random number generator to generate tokens: The tokens should be sufficiently long and unpredictable to prevent attackers from guessing or brute-forcing them.

  2. Implement token expiration and revocation: Tokens should have a limited lifetime and should be automatically revoked or expired after a certain period of time or in case of suspicious activity.

  3. Use secure communications: Use secure communication protocols such as HTTPS to transmit tokens to prevent interception and tampering.

  4. Implement proper access control: Tokens should only grant access to the resources that the user is authorized to access.

  5. Monitor token usage: Regularly monitor token usage to detect any suspicious activity, such as multiple requests from a single token or excessive usage of a single token.

  6. Use multi-factor authentication: Implement multi-factor authentication to add an extra layer of security to the token-based authentication system.

  7. Regularly update and patch software: Regularly update and patch software to ensure that any known vulnerabilities related to insecure token generation are addressed.

  8. Perform security testing: Regularly perform security testing, such as vulnerability scanning and penetration testing, to detect and address any vulnerabilities related to insecure token generation.

Conclusion

Insecure token generation is a serious security vulnerability that can allow attackers to gain unauthorized access to resources and sensitive information. This vulnerability can arise when tokens are generated using weak random number generators or predictable algorithms, or when tokens have a long lifespan without proper expiration or revocation mechanisms.

To address insecure token generation vulnerabilities, it is important to use a secure random number generator, implement proper access control and token expiration and revocation mechanisms, use secure communication protocols, monitor token usage, use encryption and hashing, regularly update and patch software, perform security testing, and provide security awareness training.

It is important for organizations to take proactive measures to identify and mitigate insecure token generation vulnerabilities to ensure the security and privacy of their systems and data.

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