Postman Workspace Leaks: When Your API Testing Tool Becomes a Data Breach 📮
Postman Workspace Leaks: When Your API Testing Tool Becomes a Data Breach 📮
How 30,000 Public Workspaces Exposed Critical Business Secrets
In December 2024, the cybersecurity world witnessed one of the most significant API security incidents in recent years. CloudSEK’s TRIAD team discovered that sensitive information, including API keys, access tokens, and refresh tokens, was leaked from 30,000 public workspaces on the Postman platform. This massive exposure affected organizations across multiple industries, from healthcare providers to payment processors, exposing them to substantial financial and reputational risks.
The irony is stark: Postman, a platform designed to streamline API development and testing for over 30 million organizations globally, became the vector for one of the most widespread credential leaks in recent memory. This incident serves as a sobering reminder that even the most useful development tools can become security liabilities when improperly configured.
The Scale of the Breach: Numbers That Demand Attention
The magnitude of this security incident cannot be overstated. A year-long investigation revealed over 30,000 publicly accessible workspaces disclosing sensitive information, including access tokens, refresh tokens, third-party API keys, and even test or demo user data.
Which Platforms Were Most Affected?
The platforms most impacted by these leaks include GitHub with 5,924 exposures, Slack with 5,552, and Salesforce with 4,206 exposures. Other compromised services included Microsoft online services, Facebook Graph API, and numerous payment processing platforms. The breadth of affected services demonstrates how interconnected modern software ecosystems have become—and how a single misconfiguration can create cascading security risks.
Industries at Risk
The leaked data spanned multiple critical sectors:
- Healthcare: Patient data and administrative systems
- Financial Services: Payment processing APIs and transaction credentials
- E-commerce: Customer information and payment gateways
- Technology: Internal systems and proprietary infrastructure
- Athletic Apparel and Retail: Supply chain and customer data
E-commerce and payment systems contributed to 3.9% of all endpoint leaks, highlighting the particular vulnerability of customer-facing businesses.
Real-World Consequences: From Theory to Threat
The Postman workspace leaks weren’t merely theoretical vulnerabilities—they resulted in tangible security breaches with real victims.
Case Study: Healthcare Provider Breach
A major healthcare firm faced potential data exposure when a public Postman workspace was discovered leaking highly sensitive information, including active ZenDesk admin credentials with full administrator privileges. This exposure could have allowed malicious actors to access patient information, manipulate support operations, and create sophisticated phishing schemes targeting vulnerable patients.
The healthcare sector operates under strict regulatory frameworks like HIPAA in the United States. Such breaches could result not only in data theft but also in massive regulatory fines and irreparable damage to patient trust.
Case Study: Payment Gateway Vulnerability
Multiple instances of Razorpay API keys were accidentally exposed in publicly shared Postman workspaces. Razorpay, a popular payment gateway platform in India, processes millions of transactions daily. The exposed keys could have enabled unauthorized transactions, financial fraud, and manipulation of payment systems.
This case exemplifies how developer oversights can directly translate into financial crimes, affecting both businesses and their customers.
Case Study: Athletic Apparel Company
A leading organization in the Athletic Apparel and Footwear industry could have been compromised when a private Postman workspace was leaked by a third-party vendor, exposing requests to the organization’s Okta Identity and Access Management system along with valid credentials and access tokens.
This incident highlights a critical modern security challenge: third-party risk. Organizations may implement robust security practices internally, only to be compromised through less secure partners and vendors.
Case Study: CRM Platform Compromise
A Postman workspace exposed a refresh token and session secrets for a CRM platform alongside an endpoint to generate access tokens. This type of exposure is particularly dangerous because it allows attackers to maintain persistent access to systems, even if initial credentials are changed.
Why Do Developers Accidentally Share Secrets?
Understanding how these leaks occurred is essential to preventing future incidents. The root causes are multifaceted, involving both technical and human factors.
1. Misunderstanding Workspace Visibility Settings
By default, Postman exposes workspaces to the internet, a design choice that has puzzled security professionals. Many developers create public workspaces without fully understanding that “public” means accessible to anyone on the internet, not just their team members.
The distinction between personal, team, private, and public workspaces often confuses users, especially those new to the platform. A developer might believe they’re sharing within their organization when they’re actually exposing data to the entire world.
2. Storing Sensitive Data in Plain Text
Postman, by default, saved sensitive data in a plain text format without any encryption, allowing anyone with access to the workspace to view potentially sensitive data. This practice, combined with insufficient understanding of security implications, created a perfect storm for data exposure.
Developers frequently embed API keys, passwords, and tokens directly in request examples, environment variables, or collection documentation. While convenient for testing, this practice becomes catastrophic when workspaces are made public.
3. Inadequate Use of Built-in Security Features
Many users chose not to utilize Postman’s secret management tools, putting sensitive data at risk. Postman offers features like secret masking, encrypted variable storage, and the Postman Vault, but these require active implementation by users.
The lack of adoption of features like “secret masking” and encrypted variable storage left sensitive credentials exposed and easily accessible in plaintext.
4. Lack of API Key Rotation
Even if a credential is leaked, prompt rotation minimizes the time it remains usable by unauthorized parties; however, many exposed keys remained active long after being leaked. This prolonged exposure allowed potential attackers to repeatedly exploit credentials, potentially gaining deeper access to systems over time.
5. Insufficient Developer Training
Many users were unaware of the visibility settings or the need to secure sensitive information within shared workspaces, and best practices for sharing and secrets management were often overlooked. Organizations failed to educate teams on the correct use of Postman’s collaboration tools or the broader security implications of API development.
The rapid adoption of API development platforms has outpaced security training, creating knowledge gaps that threat actors are eager to exploit.
6. Third-Party and Vendor Risk
Several breaches occurred not through the primary organization’s actions but through third-party vendors with access to company systems. As organizations increasingly rely on external partners for development work, the security practices of these vendors become critical—and often overlooked.
How Attackers Exploit Exposed Workspaces
Understanding the attacker’s perspective helps organizations prioritize their security efforts.
Access and Reconnaissance
An attacker finding an exposed workspace URL could extract credentials and use them to make unauthorized API requests, access sensitive data, or manipulate systems connected to the API. The public nature of these workspaces makes them easily discoverable through simple search queries.
Credential Harvesting
Once inside a public workspace, attackers can systematically harvest: - API keys for cloud services (AWS, Azure, Google Cloud) - Access tokens for authentication - Refresh tokens for persistent access - Database connection strings - Third-party service credentials
Lateral Movement
Postman allows users within the same organization to view adjacent teams, which can be used by attackers that have access to Postman to laterally move and access other teams which may contain sensitive information. A single compromised credential can become the foothold for exploring an organization’s entire infrastructure.
Data Exfiltration
Attackers can leverage exposed API keys in Postman to access and exfiltrate sensitive data, including customer information, financial records, intellectual property, and proprietary business data.
Financial Fraud
In cases where payment processing credentials are exposed, attackers can: - Process unauthorized transactions - Redirect payments to fraudulent accounts - Access customer payment information - Manipulate transaction records
Session Hijacking
Threat actors can gain control of leaked tokens by generating their own API requests to gain access to internal systems and escalate issues quickly. This allows them to impersonate legitimate users and bypass authentication mechanisms.
Postman’s Response: Too Little, Too Late?
Following the disclosure of these widespread leaks, Postman implemented several security measures.
Proactive Secret Detection
Postman has implemented proactive secret detection and user notifications when sensitive data is detected in public workspaces. The platform now scans for common patterns associated with API keys, tokens, and credentials before workspaces are made public.
Removal of Compromised Workspaces
Starting this month, Postman is removing public workspaces with known exposed secrets from the Public API Network, with owners being notified and given the opportunity to remove their exposed secrets before workspace removal.
Enhanced Alerting
The platform now provides more prominent warnings when users attempt to make workspaces public, alerting them to potential security implications.
Questions Remain
While these measures are steps in the right direction, critics argue they should have been implemented from the beginning. The default-public workspace configuration that enabled many of these leaks raises questions about Postman’s initial security-by-design philosophy.
Best Practices: Securing Your Postman Workspaces
Organizations and individual developers must take proactive steps to secure their API development environments.
1. Always Start with Private Workspaces
Workspaces can be made private by navigating to Workspace Settings for the relevant workspace and changing the team visibility to internally accessible. Never create public workspaces unless you have a specific, legitimate reason for doing so—and even then, ensure all sensitive data is removed.
2. Use Environment Variables Properly
Use environment variables to avoid hardcoding sensitive data. Users should create an environment within Postman and commit secrets directly within the environment rather than in collection variables.
Store sensitive values in the “Current Value” field of environment variables, which is not synced to Postman’s cloud servers, rather than the “Initial Value” field, which is shared with all workspace members.
3. Leverage Postman Vault
Postman Vault lets you store sensitive data, including API keys, access tokens, and passwords, as vault secrets in your local instance of Postman, with only you able to access and use your vault secrets, which aren’t synced to the Postman cloud.
The Vault provides secure, local-only storage for the most sensitive credentials, ensuring they never leave your machine.
4. Implement Regular API Key Rotation
Establish policies for rotating API keys and access tokens on a regular schedule. Even if keys aren’t known to be compromised, regular rotation limits the window of opportunity for attackers who may have obtained credentials through undiscovered leaks.
5. Enable Two-Factor Authentication
Always use a strong password based on best practices, verify your email address, and enable two-factor authentication in Postman with Google or your single sign-on identity provider.
6. Conduct Regular Security Audits
Periodic assessments ensure compliance with security standards and uncover vulnerabilities before they are exploited, including reviewing shared collections for sensitive information and misconfigurations.
Designate security champions within development teams to regularly audit workspaces, collections, and environment configurations.
7. Implement Role-Based Access Control
Assigning the Viewer role by default, then Editor and Admin roles to others on a truly as-needed basis will prevent unintentional or unapproved changes to the collection that could include sensitive information.
Not everyone needs edit access to every collection. Implement the principle of least privilege.
8. Train Your Development Teams
Train developers on API management platform features, such as workspace visibility settings, highlighting the importance of not embedding sensitive data in shared collections or environment files.
Security awareness training should be mandatory for all developers, with specific modules on API security and proper use of collaboration tools like Postman.
9. Monitor for Exposed Secrets
Implement tools to detect exposed credentials and alert teams about potential vulnerabilities, using platforms like Assetnote Surface Monitoring and CybelAngel for proactive detection of leaked API keys.
Automated monitoring can catch mistakes before they’re exploited by malicious actors.
10. Disable Team Discovery
Navigate to Team Settings within every team in your Postman organization and in Team Discovery, make sure it’s set to disabled to prevent potential lateral movement by attackers who might compromise a single account.
11. Sanitize Before Sharing
Before sharing any collection, even internally, conduct a thorough review to remove: - Real API keys and replace them with placeholder values - Production credentials - Internal system URLs and IP addresses - Customer or user data - Proprietary business logic
12. Implement a Peer Review Process
Have a peer review process for critical collections and merge changes using Postman’s collection fork and merge feature. A second set of eyes can catch security issues that the original developer might overlook.
The Broader Implications for API Security
The Postman workspace leaks represent more than just a single platform’s security issues—they reflect systemic challenges in modern software development.
The Collaboration-Security Tension
Modern development emphasizes collaboration and rapid iteration. Tools like Postman are designed to make sharing and teamwork effortless. However, this ease of collaboration can conflict with security best practices, which often require additional steps and restrictions.
Organizations must find the right balance between developer productivity and security controls, recognizing that the cost of a breach far exceeds the minor inconvenience of implementing proper security measures.
The Human Factor
Technical solutions alone cannot solve security problems rooted in human behavior. Developers working under tight deadlines may take shortcuts, like hardcoding API keys “just for now” and forgetting to remove them later. Training, culture, and accountability are as important as technical controls.
The Supply Chain Challenge
The third-party vendor breaches highlighted in this incident underscore the importance of supply chain security. Organizations must extend security requirements to partners, vendors, and contractors who have access to their systems.
The Default-Secure Imperative
The Postman leaks raise important questions about platform design. Should tools default to maximum security with options to reduce it, or maximum convenience with options to increase security? The industry is increasingly moving toward “secure by default” philosophies, and this incident will likely accelerate that trend.
Moving Forward: A Call to Action
The exposure of 30,000 Postman workspaces should serve as a wake-up call for the entire software development industry. API security cannot be an afterthought—it must be integrated into every stage of the development lifecycle.
For Organizations
- Conduct immediate audits of all Postman workspaces
- Implement mandatory security training for all developers
- Establish clear policies for API key management and rotation
- Consider implementing secrets management solutions
- Review and strengthen third-party vendor security requirements
For Individual Developers
- Review all your Postman workspaces and ensure they’re private
- Remove any exposed credentials immediately and rotate affected keys
- Learn to use security features like Postman Vault
- Stay informed about security best practices
- Think before you share—assume everything public will be seen by attackers
For Platform Providers
- Design for security by default, not as an opt-in feature
- Provide clear, prominent warnings about security implications
- Implement proactive scanning and alerting for sensitive data
- Invest in user education and documentation
- Consider liability and responsibility in platform design decisions
Conclusion: The High Cost of Convenience
The Postman workspace leaks demonstrate how quickly convenience can become catastrophe in our interconnected digital world. These vulnerabilities open doors to catastrophic consequences, from data breaches and unauthorized transactions to reputational and financial damages.
As APIs become the connective tissue of modern software, securing them must become a fundamental skill for every developer. The days of treating security as someone else’s problem are over. Every developer who creates an API, tests an endpoint, or shares a collection bears responsibility for protecting the data and systems they touch.
The good news is that most API security issues are preventable through awareness, training, and proper use of available security features. The Postman workspace leaks were not the result of sophisticated hacking techniques—they were the result of simple misconfigurations and oversights that any developer can avoid.
As we move forward, let this incident serve as a reminder: in the world of API development, what you share matters. A single public workspace, one exposed credential, or one overlooked configuration can be the difference between security and catastrophe. The tools we use to build the digital world can also be the means of its undoing—unless we commit to using them responsibly, securely, and with the vigilance they demand.
The choice is ours: treat API security as a priority, or wait for the next breach to learn the lesson again.