OWASP API1:2023 Broken Object Level Authorization (BOLA) ๐๐
Panchanan Panigrahi
Posted on February 9, 2024
To grasp this security vulnerability, it's essential to delve into the concept of Object Level Authorization first. ๐งโ๐ป๐
What is Object Level Authorization โ๐
Object level authorization is an access control mechanism that is usually implemented at the code level to validate that a user can only access the objects that they should have permission to access. ๐ซ๐ค๐
Every API endpoint that receives an ID of an object, and performs any action on the object, should implement object-level authorization checks. The checks should validate that the logged-in user has permission to perform the requested action on the requested object. ๐ค๐ฎโโ๏ธ
Failures in this mechanism typically lead to unauthorized information disclosure, modification, or destruction of all data. This is called Broken Object Level Authorization. ๐ฅ๐ซ๐
Impacts: ๐ฅ๐
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Unauthorized Access:
- Risk: Users may gain access to sensitive data or functionalities they are not supposed to access.
- Impact: Breach of confidentiality, potential exposure of critical information. ๐ง๐๏ธ
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Data Manipulation:
- Risk: Malicious users might alter or delete data they are not authorized to modify.
- Impact: Loss of data integrity, potential disruption of business processes. ๐๐
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Elevation of Privileges:
- Risk: Exploitation of broken Object Level Authorization may lead to unauthorized elevation of user privileges.
- Impact: Malicious users can perform actions reserved for higher-privileged roles, potentially causing significant damage. โ ๏ธ๐
Example Attack Scenarios ๐๐พ
Scenario 1: Unauthorized Fund Transfer in a Financial Application ๐ธ๐จ
Attack Details:
In this scenario, an attacker exploits broken Object Level Authorization in a banking application to execute unauthorized fund transfers. By manipulating the authorization checks within the application, the attacker gains access to functionalities intended only for legitimate users. Leveraging technical vulnerabilities in the code logic governing transaction permissions, the attacker crafts requests that bypass intended restrictions. ๐ญ๐ฆ๐ฐ
The attack involves the following key steps:
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Identification of Weakness:
- The attacker identifies vulnerabilities in the Object Level Authorization mechanism of the banking application, allowing them to navigate through the code and find areas with insufficient access controls. ๐๐
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Bypassing Security Controls:
- Through various techniques such as session hijacking, cookie manipulation, or exploiting flaws in authentication mechanisms, the attacker gains unauthorized access to the victim's account. ๐ช๐ค๐ช
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Transaction Tampering:
- With access to the victim's account, the attacker manipulates the application's transaction authorization protocols. This involves crafting requests that mimic legitimate transactions but are intended to initiate fund transfers to the attacker's own or another external account. ๐๐ณ๐
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Execution of Unauthorized Transactions:
- The attacker successfully executes unauthorized fund transfers using the compromised account. This could involve exploiting vulnerabilities in the transaction processing logic, allowing them to override the intended restrictions and security checks. ๐ผ๐ธ๐
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Covering Tracks:
- To avoid detection, the attacker may attempt to cover their tracks by modifying logs or manipulating transaction records. This ensures that their unauthorized activities go unnoticed for a more extended period. ๐ต๏ธโโ๏ธ๐๐
Mitigation:
Implementing stringent access controls, robust session management, and multi-factor authentication are crucial in mitigating such attacks. Regular security audits and monitoring for anomalous transactions can help detect and prevent unauthorized fund transfers. Additionally, continuous code reviews and addressing vulnerabilities in the application's logic contribute to a more resilient security posture. ๐ก๏ธ๐๐ ๏ธ
Scenario 2: Unauthorized Patient Record Access in a Healthcare System ๐ฅ๐ฉโโ๏ธ
Attack Details:
Within a healthcare system plagued by Object Level Authorization issues, an attacker exploits vulnerabilities to gain unauthorized access to patient records. The attacker, aiming to compromise sensitive medical information, manipulates the application's access controls and authentication mechanisms. ๐๐๐ป
The attack unfolds as follows:
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Identifying Access Control Weakness:
- The attacker identifies weaknesses in the Object Level Authorization mechanism, discovering areas where access controls are insufficiently enforced or improperly configured. ๐๐๐ค
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Exploiting Authentication Flaws:
- Leveraging weak authentication mechanisms, the attacker gains initial access to the application. This could involve exploiting password vulnerabilities, session management issues, or other authentication-related weaknesses. ๐คซ๐๐ป
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Navigating to Patient Records:
- With the initial access, the attacker traverses the application's data objects or manipulates URLs meant to be restricted. They exploit direct object reference flaws, allowing them to access patient records they are not authorized to view. ๐ช๐๐
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Potential Data Alteration:
- The attacker may not only view but also alter sensitive medical information. This could lead to unauthorized modifications of patient records or the extraction of confidential data for malicious purposes. ๐๐๐
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Concealing Unauthorized Access:
- To avoid detection, the attacker may attempt to cover their tracks by modifying logs or manipulating audit trails. This ensures their unauthorized access remains undetected for an extended period. ๐ต๏ธโโ๏ธ๐๐
Mitigation:
Mitigating such attacks involves implementing robust access controls, encrypting sensitive data, and conducting regular security audits. Strengthening authentication protocols, monitoring for unusual access patterns, and promptly addressing identified vulnerabilities contribute to a more secure healthcare system. ๐๐๐ก๏ธ
Scenario 3: Unauthorized Product Discounts in an E-commerce Platform ๐๐ค
Attack Details:
In an e-commerce platform with Object Level Authorization vulnerabilities, an attacker aims to gain unauthorized control over administrative functionalities. By exploiting weaknesses in the application's access controls and authentication mechanisms, the attacker manipulates pricing-related functionalities to apply unauthorized product discounts. ๐ณ๐๐
The attack unfolds through the following steps:
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Identifying Administrative Weakness:
- The attacker identifies vulnerabilities in the Object Level Authorization mechanism, focusing on areas where administrative access controls are inadequately enforced or improperly configured. ๐ต๏ธโโ๏ธ๐๐ช
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Exploiting Authentication and Session Management:
- Leveraging weaknesses in authentication methods or session management, the attacker gains unauthorized access to administrative functionalities. This could involve exploiting weak passwords, session hijacking, or other authentication-related flaws. ๐ต๏ธโโ๏ธ๐๐ช
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Navigating to Pricing Controls:
- With access to administrative features, the attacker navigates to pricing-related functionalities. They exploit direct object reference flaws
or manipulate URLs to access controls governing product prices and discounts. ๐๏ธ๐๐ธ
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Applying Unauthorized Discounts:
- The attacker modifies pricing settings, applying unauthorized discounts to products. This could lead to financial losses for the e-commerce platform as customers exploit the discounted prices. ๐ฐ๐ธ๐
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Concealing Unauthorized Access:
- To avoid detection, the attacker may attempt to cover their tracks by modifying logs or manipulating audit trails. This ensures their unauthorized access remains undetected for an extended period. ๐ต๏ธโโ๏ธ๐๐
Mitigation:
Mitigating such attacks involves implementing strong authentication protocols, robust access controls, and conducting regular security assessments. Monitoring for unusual administrative activities and promptly addressing identified vulnerabilities contribute to a more secure e-commerce platform. ๐ก๏ธ๐ฉโ๐ผ๐
How To Prevent Broken Object Level Authorization (BOLA)? ๐ก๏ธ๐ ๏ธ
Implement a proper authorization mechanism that relies on user policies and hierarchy. ๐๐ค๐๏ธ
Use the authorization mechanism to check if the logged-in user has access to perform the requested action on the record in every function that uses input from the client to access a record in the database. ๐งโ๐ป๐๐
Prefer the use of random and unpredictable values as GUIDs for records' IDs. ๐๐๐ซ
Write tests to evaluate the vulnerability of the authorization mechanism. Do not deploy changes that make the tests fail. ๐๐งช๐ซ
Conclusion ๐๐ค
Keeping an eye on Broken Object Level Authorization (BOLA) is key to stopping unauthorized access and data problems. Learning from real stories, and using strong security like access controls is super important. Your watchful eye helps create a safer online space. Stay safe, and a big thank you for caring about online security! ๐๐๐
Posted on February 9, 2024
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