07 Mar, 2023

Predictable Session ID

Vulnerability Assessment as a Service (VAaaS)

Tests systems and applications for vulnerabilities to address weaknesses.

Predictable Session ID (PSI) is a security vulnerability that occurs when session IDs are generated in a predictable or sequential manner, making it easier for an attacker to guess or predict the session ID of a user and potentially hijack their session. PSI is a common issue in web applications and can be exploited by attackers to gain unauthorized access to user accounts, perform malicious activities or steal sensitive information. It is important for developers to use strong and random session ID generation techniques to prevent PSI vulnerabilities.

Example of vulnerable code on different programming languages:


in Python:

				
					import random
from flask import Flask, session

app = Flask(__name__)
app.secret_key = 'secret'

@app.route('/')
def index():
    if 'user_id' not in session:
        session['user_id'] = random.randint(1, 100)
    return 'Hello, user %d!' % session['user_id']

				
			

 

In this example, the session ID is generated using the random module in Python. However, the random.randint() function generates a predictable sequence of numbers, making the session ID vulnerable to prediction attacks.

• in PHP:

				
					session_start();
if (!isset($_SESSION['user_id'])) {
    $_SESSION['user_id'] = rand(1, 100);
}
echo "Hello, user " . $_SESSION['user_id'] . "!";

				
			


This PHP code uses the rand() function to generate a random number between 1 and 100 as the session ID. However, rand() is not a cryptographically secure random number generator and can produce predictable sequences of numbers, leading to a PSI vulnerability.

• in Java:

				
					import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.Random;

public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
        HttpSession session = request.getSession(true);
        if (session.getAttribute("user_id") == null) {
            Random random = new Random();
            int userId = random.nextInt(100) + 1;
            session.setAttribute("user_id", userId);
        }
        String message = "Hello, user " + session.getAttribute("user_id") + "!";
        response.getWriter().write(message);
    }
}

				
			


This Java servlet code uses the Random class to generate a random number between 1 and 100 as the session ID. However, Random is not a cryptographically secure random number generator and can produce predictable sequences of numbers, leading to a PSI vulnerability. To prevent this vulnerability, developers should use a cryptographically secure random number generator, such as SecureRandom, to generate session IDs.

Examples of exploitation Predictable Session ID

Session Hijacking:

An attacker can use a PSI vulnerability to predict a user’s session ID and impersonate them. They can then access the user’s account and perform actions on their behalf, such as making unauthorized purchases or modifying sensitive data.

Cross-Site Scripting (XSS):

An attacker can inject malicious code into a website that can read a user’s session ID and use it to perform actions on the user’s behalf. This can lead to a variety of attacks, such as stealing sensitive information or modifying user data.

Session Fixation:

An attacker can set a user’s session ID to a known value (such as one that they have predicted) before the user logs in. When the user logs in, their session will be associated with the attacker’s session ID, giving the attacker access to the user’s account.

Brute Force Attacks:

If an attacker can predict a sequence of session IDs, they can use this knowledge to launch a brute force attack on the application. This involves repeatedly attempting to log in with different session IDs until a valid one is found.

Privilege escalation techniques for Predictable Session ID

Session Fixation:

In a session fixation attack, the attacker sets a known session ID for the user before they log in, which allows the attacker to take over the user’s session once they log in. The attacker can then use this elevated access to perform actions that they would not normally be authorized to perform.

Session Hijacking:

In a session hijacking attack, the attacker predicts the session ID of a user and takes over their session. The attacker can then use the user’s elevated access to perform actions that they would not normally be authorized to perform.

Cross-Site Scripting (XSS):

An attacker can inject malicious code into a website that reads the user’s session ID and uses it to perform actions on the user’s behalf. The attacker can use this to escalate their privileges and perform actions that they would not normally be authorized to perform.

Brute Force Attacks:

An attacker can use a brute force attack to guess session IDs in sequence, trying each one until they gain access to a user’s session. Once they have access to the user’s session, they can use it to escalate their privileges and perform actions that they would not normally be authorized to perform.

General methodology and checklist for Predictable Session ID

Methodology:

  1. Identify session management functionality: Start by identifying where session management functionality is implemented in the application. This may include session initialization, session ID generation, and session expiration.

  2. Identify session ID generation techniques: Once you have identified session management functionality, determine how session IDs are generated in the application. This may include inspecting code or configuration files to see if predictable or weak random number generation techniques are being used.

  3. Test session ID generation: Test the session ID generation functionality to determine whether session IDs can be predicted or brute-forced. You can use tools such as Burp Suite or OWASP ZAP to automate this process.

  4. Verify session ID uniqueness: Verify that session IDs are unique to each user and are not being shared between multiple users. This can be done by logging in as multiple users simultaneously and verifying that each user has a unique session ID.

  5. Verify session ID expiration: Verify that session IDs expire after a period of inactivity or after a set time period. This can be done by logging in as a user, waiting for the session to expire, and attempting to access the application again.

  6. Report findings: Document any vulnerabilities found and report them to the development team. Provide recommendations for how to address any vulnerabilities found, such as using cryptographically secure random number generators for session ID generation.

  7. Retest: After the development team has addressed the vulnerabilities, retest to ensure that the vulnerabilities have been properly addressed and that no new vulnerabilities have been introduced.

Checklist:

  1. Identify the session management functionality in the application.

  2. Determine how session IDs are generated in the application.

  3. Verify that session IDs are generated using a strong, random number generator.

  4. Determine the session ID length and verify that it is sufficient to prevent guessing attacks.

  5. Verify that session IDs are unique to each user.

  6. Verify that session IDs are not being shared between multiple users.

  7. Verify that session IDs expire after a period of inactivity or after a set time period.

  8. Determine the session ID storage mechanism and verify that it is secure (e.g., using HTTPS).

  9. Determine the session ID transmission mechanism and verify that it is secure (e.g., using secure cookies).

  10. Test the application to ensure that session IDs cannot be predicted or brute-forced.

  11. Test the application to ensure that session IDs cannot be leaked or stolen (e.g., through cross-site scripting attacks).

  12. Document any vulnerabilities found and report them to the development team.

  13. Provide recommendations for how to address any vulnerabilities found, such as using cryptographically secure random number generators for session ID generation.

  14. Retest the application after the development team has addressed the vulnerabilities to ensure that they have been properly addressed and that no new vulnerabilities have been introduced.

Tools set for exploiting Predictable Session ID

Automated Tools:

  • Burp Suite: A widely used web application security testing tool that includes automated and manual vulnerability scanning, as well as tools for intercepting and modifying web traffic.

  • OWASP ZAP: An open source web application security testing tool that includes automated and manual vulnerability scanning, as well as tools for intercepting and modifying web traffic.

  • Nikto: An open source web server scanner that identifies common vulnerabilities and misconfigurations.

  • Acunetix: A web vulnerability scanner that automates the process of identifying vulnerabilities in web applications, including Predictable Session ID vulnerabilities.

  • Nessus: A network vulnerability scanner that can also be used to identify vulnerabilities in web applications.

  • AppScan: A web vulnerability scanner that automates the process of identifying vulnerabilities in web applications, including Predictable Session ID vulnerabilities.

  • Qualys: A cloud-based vulnerability management platform that includes automated scanning and reporting for web application vulnerabilities.

  • Netsparker: A web application security scanner that includes automated and manual testing for vulnerabilities, including Predictable Session ID vulnerabilities.

  • Vega: An open source web application security testing platform that includes automated and manual testing for vulnerabilities, including Predictable Session ID vulnerabilities.

  • Skipfish: An open source web application security testing tool that includes automated scanning and reporting for web application vulnerabilities, including Predictable Session ID vulnerabilities.

Manual Tools:

  • HTTP proxy: A tool that allows an attacker to intercept and modify web traffic, including session ID values.

  • cURL: A command-line tool for transferring data over a network, which can be used to simulate web requests and test for Predictable Session ID vulnerabilities.

  • Browser Developer Tools: Many web browsers include developer tools that can be used to inspect and modify web traffic, including session ID values.

  • Tamper Data: A browser plugin that allows users to intercept and modify web traffic, including session ID values.

  • LiveHTTPHeaders: A browser plugin that allows users to view and modify HTTP headers, including session ID values.

  • Wireshark: A network protocol analyzer that can be used to capture and analyze network traffic, including session ID values.

  • Fiddler: A web debugging proxy that can be used to intercept and modify web traffic, including session ID values.

  • Charles Proxy: A web debugging proxy that can be used to intercept and modify web traffic, including session ID values.

  • BeEF: The Browser Exploitation Framework is a tool that can be used to test the security of web browsers, including their ability to resist session hijacking attacks.

  • SQLMap: A tool that can be used to automate the process of identifying SQL injection vulnerabilities in web applications, which can often be used to obtain session ID values.

Average CVSS score of stack Predictable Session ID

The CVSS (Common Vulnerability Scoring System) score of vulnerabilities related to Predictable Session ID can vary widely depending on the specific vulnerability and its impact on the system. In general, Predictable Session ID vulnerabilities can lead to session hijacking, which can result in unauthorized access to sensitive information or functionality within the application.

The CVSS score for a vulnerability is calculated based on factors such as the impact on confidentiality, integrity, and availability, as well as the ease of exploitation and the complexity of mitigating the vulnerability. Because Predictable Session ID vulnerabilities can have varying degrees of impact, the CVSS score can range from relatively low (e.g. 4 or 5) to high (e.g. 8 or 9).

In general, however, Predictable Session ID vulnerabilities are considered to be moderately severe vulnerabilities, as they can lead to unauthorized access to sensitive data or functionality within the application. It is important for organizations to regularly assess their applications for Predictable Session ID vulnerabilities and to take appropriate measures to mitigate them in order to reduce the risk of unauthorized access and other security incidents.

The Common Weakness Enumeration (CWE)

• CWE-613: Insufficient Session Expiration: This weakness occurs when a web application does not properly expire user sessions, allowing an attacker to use a session ID after it should have been invalidated.

• CWE-384: Session Fixation: This weakness occurs when a web application allows an attacker to fixate the session ID of a victim user, enabling the attacker to hijack the user’s session.

• CWE-200: Information Exposure: This weakness occurs when sensitive information, such as session IDs, is disclosed to an attacker, enabling the attacker to hijack a user’s session.

• CWE-399: Resource Management Errors: This weakness occurs when a web application does not properly manage resources, including session IDs, leading to vulnerabilities such as session hijacking.

• CWE-276: Incorrect Default Permissions: This weakness occurs when a web application sets default permissions for sensitive resources, such as session IDs, that are too permissive, allowing unauthorized access.

• CWE-362: Race Condition: This weakness occurs when a web application does not properly handle concurrent access to resources, including session IDs, leading to vulnerabilities such as session hijacking.

• CWE-285: Improper Authorization: This weakness occurs when a web application does not properly enforce access controls, including for session IDs, allowing unauthorized access.

• CWE-294: Authentication Bypass by Spoofing: This weakness occurs when a web application can be tricked into accepting a fake or spoofed session ID, enabling an attacker to hijack the user’s session.

• CWE-330: Use of Insufficiently Random Values: This weakness occurs when a web application uses predictable or insufficiently random values for session IDs, making them vulnerable to guessing or enumeration attacks.

• CWE-532: Information Leak Through Predictable Resource Location: This weakness occurs when a web application uses predictable or easily guessable URLs or other resource identifiers, including session IDs, making them vulnerable to enumeration attacks.

Top 10 CVES related to Predictable Session ID

• CVE-2021-46010 – Totolink A3100R V5.9c.4577 suffers from Use of Insufficiently Random Values via the web configuration. The SESSION_ID is predictable. An attacker can hijack a valid session and conduct further malicious operations.

• CVE-2020-9502 – Some Dahua products with Build time before December 2019 have Session ID predictable vulnerabilities. During normal user access, an attacker can use the predicted Session ID to construct a data packet to attack the device.

• CVE-2020-27743 – libtac in pam_tacplus through 1.5.1 lacks a check for a failure of RAND_bytes()/RAND_pseudo_bytes(). This could lead to use of a non-random/predictable session_id.

• CVE-2018-11742 – NEC Univerge Sv9100 WebPro 6.00.00 devices have Cleartext Password Storage in the Web UI.

• CVE-2018-11741 – NEC Univerge Sv9100 WebPro 6.00.00 devices have Predictable Session IDs that result in Account Information Disclosure via Home.htm?sessionId=#####&GOTO(8) URIs.

• CVE-2014-8272 – The IPMI 1.5 functionality in Dell iDRAC6 modular before 3.65, iDRAC6 monolithic before 1.98, and iDRAC7 before 1.57.57 does not properly select session ID values, which makes it easier for remote attackers to execute arbitrary commands via a brute-force attack.

• CVE-2013-4732 – ** DISPUTED ** The administrative web server on the Digital Alert Systems DASDEC EAS device through 2.0-2 and the Monroe Electronics R189 One-Net EAS device through 2.0-2 uses predictable session ID values, which makes it easier for remote attackers to hijack sessions by sniffing the network. NOTE: VU#662676 states “Monroe Electronics could not reproduce this finding.”

• CVE-2012-6571 – The HTTP module in the (1) Branch Intelligent Management System (BIMS) and (2) web management components on Huawei AR routers and S2000, S3000, S3500, S3900, S5100, S5600, and S7800 switches uses predictable Session ID values, which makes it easier for remote attackers to hijack sessions via a brute-force attack.

• CVE-2012-2681 – Cumin before 0.1.5444, as used in Red Hat Enterprise Messaging, Realtime, and Grid (MRG) 2.0, uses predictable random numbers to generate session keys, which makes it easier for remote attackers to guess the session key.

• CVE-2010-4304 – The web interface in Cisco Unified Videoconferencing (UVC) System 3545, 5110, 5115, and 5230; Unified Videoconferencing 3527 Primary Rate Interface (PRI) Gateway; Unified Videoconferencing 3522 Basic Rate Interfaces (BRI) Gateway; and Unified Videoconferencing 3515 Multipoint Control Unit (MCU) uses predictable session IDs based on time values, which makes it easier for remote attackers to hijack sessions via a brute-force attack, aka Bug ID CSCti54048.

Predictable Session ID exploits

  • Session Hijacking: This exploit involves an attacker stealing a user’s session ID and using it to gain unauthorized access to the application or system.

  • Session Fixation: This exploit involves an attacker forcing a victim user to use a known session ID, which the attacker can then use to hijack the user’s session.

  • Man-in-the-Middle (MitM) Attack: This exploit involves an attacker intercepting the communication between the user and the server and stealing the session ID in transit.

  • Cross-Site Scripting (XSS) Attack: This exploit involves an attacker injecting malicious code into a web page or application, which can then steal the session ID from the user’s browser.

  • Cross-Site Request Forgery (CSRF) Attack: This exploit involves an attacker tricking a victim user into executing a malicious request, which can then steal the session ID or perform other unauthorized actions.

  • Session Replay: This exploit involves an attacker capturing a valid session ID and replaying it at a later time to gain unauthorized access.

  • Brute-Force Attack: This exploit involves an attacker guessing or brute-forcing session IDs to gain unauthorized access.

  • Predictable Value Enumeration: This exploit involves an attacker identifying predictable session ID values and using them to gain unauthorized access.

  • Session Fixation via Malicious Links: This exploit involves an attacker sending a victim user a malicious link that sets a known session ID, which the attacker can then use to hijack the user’s session.

  • Cookie Theft: This exploit involves an attacker stealing the session ID stored in a user’s browser cookie, enabling the attacker to gain unauthorized access to the application or system.

Practicing in test for Predictable Session ID

Understand the basics: Learn about session management, how session IDs work, and the common vulnerabilities associated with Predictable Session ID.

Identify the areas of concern: Analyze the web application’s architecture, design, and implementation, and identify the areas of the application that could be susceptible to Predictable Session ID vulnerabilities.

Use testing tools: Use automated testing tools such as OWASP ZAP, Burp Suite, and Nmap, to scan for Predictable Session ID vulnerabilities and generate reports.

Conduct manual testing: Perform manual testing to identify potential vulnerabilities in the application. This can include manipulating session IDs and cookies, intercepting traffic, and trying to access unauthorized areas of the application.

Perform fuzz testing: Use fuzz testing techniques to test the application’s input fields and test if the application handles unexpected input or invalid session IDs correctly.

Analyze results and generate reports: Analyze the results of the automated and manual testing, and generate reports that outline the vulnerabilities identified, their impact, and possible mitigation measures.

Repeat testing: Perform regular testing to ensure that the vulnerabilities have been mitigated, and new vulnerabilities have not been introduced.

For study Predictable Session ID

Understand what is meant by Predictable Session ID: Get familiar with what a session ID is, how it’s generated, and the concept of Predictable Session ID vulnerabilities.

Learn about session management: Study different session management techniques, such as cookie-based, URL-based, and token-based authentication.

Understand the risks associated with Predictable Session ID: Learn about the different types of attacks that can be carried out through Predictable Session ID vulnerabilities, such as session hijacking, session fixation, and man-in-the-middle attacks.

Study web application security: Get familiar with web application security, including common vulnerabilities such as SQL injection, cross-site scripting, and CSRF.

Learn about security testing techniques: Study different security testing techniques, including automated testing with tools such as OWASP ZAP, Burp Suite, and Nmap, as well as manual testing techniques.

Practice testing for Predictable Session ID vulnerabilities: Practice testing web applications for Predictable Session ID vulnerabilities using the techniques you’ve learned.

Stay up-to-date with the latest vulnerabilities and mitigation techniques: Keep up-to-date with the latest Predictable Session ID vulnerabilities and mitigation techniques through websites such as the OWASP Top 10 and security-focused blogs.

Books with review of Predictable Session ID

“The Web Application Hacker’s Handbook: Finding and Exploiting Security Flaws” by Dafydd Stuttard and Marcus Pinto: This book provides an overview of web application security and covers common vulnerabilities, including Predictable Session ID. It includes practical examples, case studies, and testing techniques.

“Web Security Testing Cookbook” by Paco Hope and Ben Walther: This book provides a collection of recipes for testing web application security, including Predictable Session ID. It includes examples of vulnerabilities and how to mitigate them.

“Black Hat Python: Python Programming for Hackers and Pentesters” by Justin Seitz: This book covers Python programming for security testing, including testing for Predictable Session ID vulnerabilities. It includes examples of network and web application security testing.

“Mastering Modern Web Penetration Testing” by Prakhar Prasad: This book covers web application security testing, including testing for Predictable Session ID vulnerabilities. It includes practical examples, tools, and testing techniques.

“The Tangled Web: A Guide to Securing Modern Web Applications” by Michal Zalewski: This book covers web application security, including common vulnerabilities, such as Predictable Session ID. It includes case studies, testing techniques, and practical examples.

“Penetration Testing: A Hands-On Introduction to Hacking” by Georgia Weidman: This book covers penetration testing techniques, including web application security testing and testing for Predictable Session ID vulnerabilities. It includes practical examples and hands-on exercises.

“Professional Penetration Testing: Creating and Operating a Formal Hacking Lab” by Thomas Wilhelm: This book covers the setup and operation of a penetration testing lab, including web application security testing and testing for Predictable Session ID vulnerabilities.

“Hacking Web Apps: Detecting and Preventing Web Application Security Problems” by Mike Shema: This book covers web application security testing, including testing for Predictable Session ID vulnerabilities. It includes practical examples, testing techniques, and case studies.

“Security Testing Handbook for Banking Applications” by Shirish Padalkar: This book covers security testing for banking applications, including web application security testing and testing for Predictable Session ID vulnerabilities. It includes practical examples, testing techniques, and case studies.

“Mastering Kali Linux for Advanced Penetration Testing” by Vijay Kumar Velu: This book covers advanced penetration testing techniques, including web application security testing and testing for Predictable Session ID vulnerabilities. It includes practical examples, tools, and testing techniques.

List of payloads Predictable Session ID

  • A fixed value, such as “12345”

  • A sequential value, such as “1”, “2”, “3”, etc.

  • A timestamp value, such as the current UNIX timestamp

  • A UUID value, such as “550e8400-e29b-41d4-a716-446655440000”

  • A hash value, such as the SHA-256 hash of a fixed string

  • A random value generated by a scripting language or tool, such as Python’s secrets module or Burp Suite’s Intruder tool

  • A value based on a user’s IP address or other unique identifier

  • A value based on the current date and time, such as “20220308-1315” for March 8th, 2022 at 1:15 PM

  • A value based on a user’s browser fingerprint, such as the result of running the fingerprintjs2 library

  • A value based on a secret key known only to the server, such as a hash of the session ID concatenated with the secret key.

How to be protected from Predictable Session ID

  1. Use a strong session ID generation algorithm: Implement a session ID generation algorithm that produces unpredictable, unique values for each session. Use a cryptographically secure random number generator and a long, complex seed value to create the session ID.

  2. Use secure session ID storage: Ensure that session IDs are not stored in URLs or other insecure locations, and that they are encrypted when stored on the server or in cookies.

  3. Implement session expiration: Set an appropriate session timeout value and invalidate session IDs after a certain amount of inactivity.

  4. Use secure communication channels: Encrypt all communications between the client and server using HTTPS, and enforce the use of secure cookies that are marked as HttpOnly and Secure.

  5. Conduct regular vulnerability assessments and penetration testing: Test your application regularly for Predictable Session ID vulnerabilities and other security issues, and take action to address any vulnerabilities that are found.

  6. Follow best practices for web application security: Implement other security measures, such as input validation, access controls, and logging and monitoring, to protect against a wide range of web application attacks.

Conclusion

Predictable Session ID vulnerabilities are a serious threat to the security and privacy of web applications. Attackers can exploit these vulnerabilities to hijack user sessions, steal sensitive information, and carry out a wide range of other attacks. To mitigate this risk, it is essential to implement a strong session ID generation algorithm, use secure session ID storage, set appropriate session timeout values, and follow best practices for web application security. Additionally, conducting regular vulnerability assessments and penetration testing can help to identify and address Predictable Session ID vulnerabilities before they can be exploited by attackers. By taking these steps, web application developers and administrators can help to protect their applications and their users from this common and dangerous security vulnerability.

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