An API key is a small string of characters. It does not look dangerous. It does not trigger warnings when pasted into a Slack message or a Google Doc. There is no alarm when it gets committed to a Git repository or included in an email to a contractor.
But that small string often represents unrestricted access to cloud infrastructure, payment processing systems, customer databases, or third-party services billed by usage. When it ends up in the wrong place, the consequences are disproportionate to how easy it was to share.
How Credentials End Up Exposed
Credential leaks rarely happen through sophisticated attacks. They happen through normal workflows:
Chat Messages
A developer asks for the Stripe API key in Slack. A colleague pastes it into the channel. Three months later, a former employee — whose Slack access was revoked but whose email archive still exists — still has that credential. Or the channel gets accidentally converted to public. Or a Slack integration logs all messages to an external service.
Shared Documents
Teams maintain “credentials docs” in Google Docs, Notion, or Confluence. These documents persist indefinitely, accumulate outdated credentials alongside current ones, and have access controls that drift as team membership changes. A shared link meant for three people may be accessible to thirty within a year.
Git Repositories
The most common and most dangerous vector. API keys committed to Git persist in the repository history even after the offending commit is removed. A git revert removes the key from the current tree but not from the commit history. Even in private repositories, this creates a persistent exposure point.
GitHub’s own research has found that millions of secrets are committed to public repositories every year. But private repositories are not immune — a single collaborator with read access can extract every secret from the full history.
Environment Variables in CI/CD Logs
Build systems often print environment variables during debugging. A printenv statement added during troubleshooting, or a test framework that logs configuration on startup, can write credentials to build logs. Those logs are often retained for weeks or months and accessible to anyone with CI/CD dashboard access.
Email and Attachments
Credentials sent via email are stored on the sender’s and recipient’s mail servers, in sent folders, in backup systems, and potentially in compliance archives. Forwarding a credential email — intentionally or by accident — multiplies the exposure. And email headers are transmitted in plaintext even when the body is encrypted, potentially revealing the fact that credentials were shared.
What Can Go Wrong
The consequences of credential exposure depend on what the credential grants access to, but common scenarios include:
Unauthorized API Usage and Financial Exposure
Cloud service API keys (AWS, GCP, Azure) often carry permissions to provision resources. An exposed AWS key can be used to spin up cryptocurrency mining instances within minutes. The victim does not discover the breach until the monthly bill arrives — sometimes showing charges of tens of thousands of dollars.
This is not theoretical. AWS credential abuse is so common that AWS has built automated detection systems specifically for this scenario. But detection is reactive. The charges are incurred before the key is revoked.
Data Exfiltration
Database credentials or API keys with read access to customer data can be used for silent, large-scale data extraction. Unlike a brute-force attack that triggers rate limiting and alerts, a valid credential provides access that looks legitimate. Exfiltration through valid credentials is significantly harder to detect and may continue for weeks or months before discovery.
Supply Chain Attacks
If a leaked credential grants access to a package registry (npm, PyPI, RubyGems), an attacker can publish malicious versions of internal packages. Downstream consumers — including your own build systems — pull the compromised package automatically. The blast radius extends far beyond the initial credential leak.
Lateral Movement
A single credential often provides a foothold for further access. A staging database credential may use the same password pattern as production. An API key for one service may work for another in the same organization. Attackers routinely use a single leaked credential to map internal infrastructure and escalate access.
Why “Just Rotate It” Is Insufficient
Credential rotation is essential — but it is a remediation step, not a prevention strategy. Rotation has limitations:
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Rotation does not remove the old value from persistent stores. If the credential was shared in Slack, the old value remains in the message history. If it was committed to Git, it remains in the repository history. Rotation creates a new valid credential but does not invalidate the exposure of the old one.
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Rotation is often incomplete. A credential may be used in multiple systems — environment variables, CI/CD secrets, deployment configurations, third-party integrations. Missing even one location during rotation causes outages.
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Rotation windows leave gaps. Between the time a credential is compromised and the time it is rotated, the attacker has valid access. If the leak is not detected quickly, this window can extend for days or weeks.
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Rotation fatigue leads to weak practices. Teams that rotate frequently sometimes adopt shorter or more predictable credentials to reduce the operational burden, inadvertently weakening security.
Handling Credentials Properly
Preventing credential exposure requires addressing the sharing mechanism, not just the credential lifecycle:
Use a Secrets Manager for Persistent Credentials
For credentials that services need at runtime — database passwords, API keys, encryption keys — use a dedicated secrets manager (HashiCorp Vault, AWS Secrets Manager, Doppler). These systems provide centralized storage, access audit logging, automatic rotation, and fine-grained access controls.
Use Encrypted, Ephemeral Sharing for Person-to-Person Transfer
When a credential needs to move from one person to another — during onboarding, vendor handoffs, or incident response — use a tool that encrypts the credential before it leaves the sender’s device and deletes the shared copy after access.
The characteristics to look for:
- Client-side encryption so the sharing platform cannot read the credential
- Expiration so the credential does not persist in a third-party system
- Download limits so the credential is accessed exactly the intended number of times
- No persistent copies so there is nothing to leak from the sharing platform later
Implement Pre-Commit Scanning
Add secret-scanning tools to your Git workflow. Tools like GitLeaks, TruffleHog, or GitHub’s built-in secret scanning detect credentials in commits before they reach the remote repository. Configure these as pre-commit hooks so developers receive immediate feedback.
Audit Existing Exposure
Before implementing new practices, audit your current exposure:
- Search Slack history for patterns matching API keys, connection strings, and common credential formats
- Scan Git history across all repositories for committed secrets
- Review shared documents for credential lists
- Check CI/CD logs for printed environment variables
The results of this audit will likely be uncomfortable. That discomfort is proportional to the value of addressing the exposure.
The Cost of Inaction
Credential leaks are among the most common causes of security incidents, and among the most preventable. The fix is not a new technology or an expensive tool — it is a change in how credentials move between people.
Stop pasting credentials into chat. Stop emailing API keys. Stop maintaining shared credential documents with no expiration or access controls.
Encrypt credentials before sharing them. Set expiration policies. Use separate channels for the link and the password. Delete credentials from shared systems after they have been received.
The effort required is minimal. The risk reduction is substantial.