How Your Credentials Get Leaked and What Happens Next

Credential leaks have become alarmingly common in today’s digital landscape. What’s more concerning is that your passwords may already be circulating in private channels without your knowledge. According to recent statistics, approximately 15 billion compromised credentials are available on the public internet, with millions of new credentials being leaked daily. Even more alarming, malware targeting credential stores jumped from 8% of samples in 2023 to 25% in 2024, a threefold increase.

The Invisible Threat: How Your Credentials Become Compromised

Data Breaches: The Source of Billions of Leaked Credentials

Every year, billions of personal information documents are stolen in data breaches. These breaches often include usernames, passwords, and sometimes even security question answers. Recent examples demonstrate that no organization is immune:

• In 2023, genetics company 23andMe lost one million data lines due to a credential stuffing attack
• PayPal had login credentials for 35,000 users compromised in December 2022
• Norton LifeLock saw 925,000 accounts targeted in a credential attack in 2023
• Microsoft acknowledged a coordinated credential stuffing attack from November 2023 to January 2024 by a Russian state-sponsored actor
• Cisco’s Duo (an MFA company) suffered a credential stuffing attack in April 2024, putting over 40,000 customers’ message logs at risk

Beyond Breaches: Other Ways Your Credentials Get Stolen

Phishing Attacks: Cybercriminals trick users into revealing login credentials via fraudulent emails, websites, or social engineering tactics. These deceptive messages appear to come from legitimate sources, manipulating users into voluntarily divulging their credentials.

Malware, Infostealer, and Keyloggers: Specialized malware variants like info-stealers extract passwords, cookies, and authentication tokens from infected systems. These credentials are then sent to command and control servers before being distributed through private channels.

Targeted Attacks: Sophisticated threat actors conduct targeted campaigns against specific individuals or organizations, using customized approaches that blend technical exploits with social engineering. These attacks often target high-value individuals with access to sensitive systems or data.

Third-Party and B2B Partner Breaches: Your credentials can be compromised not through your security failures but through breaches at your business partners or third-party vendors. The 2025 cybersecurity landscape shows a significant increase in supply chain attacks targeting these relationships.

Credential Leak Due to Human Error: Simple human mistakes are a surprisingly common source of credential exposure. Developers accidentally commit credentials to public GitHub repositories, employees share passwords in unencrypted emails or messaging platforms, and IT staff misconfigured cloud storage buckets, making them publicly accessible. In 2024, researchers found over 800,000 exposed credentials across public GitHub repositories, many belonging to enterprise environments.

Social Engineering: Attackers exploit human psychology rather than technical vulnerabilities. These techniques include pretexting (creating a fabricated scenario), baiting, or tailgating (following authorized personnel into secure areas).

SIM Swapping: Criminals call your cell service provider to activate a new SIM card, taking control of your phone number. This allows them to receive authentication codes meant for you, bypassing two-factor authentication.

The Dark Journey of Your Leaked Credentials

What happens after your credentials are stolen is often invisible to you but follows a predictable pattern:

1. Initial Collection and Private Trading

Once stolen, your credentials don’t immediately appear on public forums. Instead, they’re first traded in exclusive marketplaces, private Telegram channels, and closed cybercriminal communities. This early trading phase can last weeks or months before credentials reach wider distribution.

2. Advanced Persistent Threat (APT) Operations

Nation-state actors and sophisticated criminal groups use stolen credentials in long-term APT campaigns. These operations involve maintaining a persistent presence within compromised networks, often for months or years, while slowly extracting valuable data or establishing backdoors for future exploitation.

3. Source Code and API Key Theft

Attackers increasingly target developer credentials to access source code repositories and API keys. The recent DeepSeek data leak exposed 11,908 live API keys, passwords, and authentication tokens embedded in publicly scraped web data. These stolen keys and source code can be used for further attacks, intellectual property theft, or to create backdoored versions of legitimate software.

4. Private VPN Access Exploitation

Compromised VPN credentials provide attackers with a direct path into corporate networks. Once attackers obtain your organization’s VPN credentials, they can bypass perimeter security and gain internal network access, moving laterally through systems while appearing as legitimate users. This access allows them to exfiltrate sensitive data, deploy malware, or establish persistent backdoors.

5. Personal Threats and Voice Phishing

Stolen credentials can lead to highly personalized attacks. Voice phishing (vishing) has seen a massive 442% increase between the first and second half of 2024. Attackers use stolen personal information to craft convincing voice phishing scenarios, often impersonating help desk staff or executives to trick victims into providing additional credentials or access.

6. Credential Validation and Organization

Attackers validate stolen credentials to determine which ones are still active. They organize them into “combo lists” or “dictionaries” traded and sold on the dark web. These lists become more valuable when they contain freshly stolen, valid credentials.

7. Exploitation Through Various Attack Methods

Credential Stuffing: Attackers use automated tools to test stolen username-password combinations across multiple websites, exploiting the common habit of password reuse. With a 2% success rate, one million stolen credentials can take over 20,000 accounts.

Account Takeover (ATO): Once attackers gain access to your accounts, they can conduct unauthorized purchases, steal sensitive information, initiate financial transactions, or perpetrate identity theft.

Business Email Compromise (BEC): Stolen corporate email credentials enable sophisticated social engineering scams, often targeting financial departments.

Privilege Escalation and Lateral Movement: After gaining initial access, attackers use compromised credentials to move through internal systems, seeking higher-value targets and expanding their reach.

The AI Evolution: How Credential Attacks Are Getting Worse

The landscape of credential attacks is evolving rapidly with the introduction of AI-powered tools. In 2025, we’re seeing a concerning trend with Computer-Using Agents, a new AI agent enabling low-cost, low-effort automation of everyday web tasks.

OpenAI’s Operator, for example, can perform web tasks like a human—seeing and interacting with pages naturally. Unlike other automated solutions, interacting with new sites requires no custom implementation or coding, making it a scalable option for attackers targeting multiple platforms.

Researchers have already demonstrated how these AI agents can:

• Identify which companies have existing tenants on various apps
• Attempt to login to app tenants with provided credentials
• Perform in-app actions once access is gained

This evolution makes credential attacks more efficient and challenging to detect, as AI can mimic human behavior patterns that might bypass traditional security measures.

Real-World Scenarios: How Leaked Credentials Are Used

Scenario 1. Corporate Account Compromise Leading to Supply Chain Attack

When an employee’s credentials are compromised, attackers can access internal systems. In one recent case, attackers used stolen administrator credentials to breach a virtual private network (VPN) and infiltrate an agency’s internal network. Once inside, they used additional stolen credentials found within the network to escalate their privileges further, eventually posting sensitive data on a dark web marketplace.

Scenario 2 Financial Fraud Through Credential Stuffing

In February 2024, Motilal Oswal Financial Services, a prominent Indian brokerage firm, fell victim to a cyberattack by the LockBit ransomware gang. The attackers claimed to have compromised confidential data belonging to more than 6 million clients, potentially exposing names, addresses, contact details, and financial information.

Scenario 3 SIM Swap Leading to Cryptocurrency Theft

SIM swap fraud occurs when criminals call your cell service provider to activate a new SIM card under their control. With access to your phone number, they can receive two-factor authentication codes sent via SMS. This technique is particularly devastating for cryptocurrency holders, as attackers can bypass security measures to access and drain digital wallets.

Scenario 4 Corporate VPN Access and Source Code Theft

Attackers who obtain developer credentials can use them to connect to corporate VPNs and access sensitive internal resources. In a high-profile case, Samsung experienced a major security breach when attackers used leaked developer credentials to access the company’s VPN, allowing them to steal approximately 190GB of confidential data including source code for Samsung Knox security and algorithms for biometric unlock operations. This breach compromised intellectual property and potentially exposed security vulnerabilities that could be exploited in future attacks.

Scenario 5 Voice Phishing Attack on Corporate Help Desk

CrowdStrike’s 2025 threat report documented a massive 442% increase in voice phishing between the first and second half of 2024. In one notable case, attackers called a company’s help desk, impersonating an executive needing an urgent password reset. After successfully obtaining new credentials, they accessed the executive’s email account and initiated fraudulent wire transfers to offshore accounts.

Scenario 6 WhatsApp Spyware Targeting Journalists

In February 2025, Meta confirmed that WhatsApp users, including journalists and members of civil society, were targeted by a sophisticated spyware attack. The attackers used stolen credentials to deploy spyware that could monitor communications and extract sensitive information from victims’ devices.

Protecting Your Credentials Essential Strategies

1. Create Strong, Unique Passwords

Use passwords at least 15-20 characters long, including a mix of uppercase and lowercase letters, numbers, and symbols. Consider using passphrases, which are a series of random words separated by spaces, as they’re easier to remember while still providing strong security.

Avoid using obvious passwords like “password123” or “asdf1234!!,” which thousands of people use. Instead, create something unique that isn’t based on personal information or common phrases.

2. Never Reuse Passwords Across Multiple Accounts

Password reuse is one of the most significant vulnerabilities exploited by attackers. When credentials from one site are leaked, attackers immediately try them on other popular services. Use a different password for each account, especially for high-value accounts like email, banking, and social media.

3. Use a Password Manager

With the many accounts most people maintain, remembering unique passwords for each is nearly impossible. Password managers create, store, and auto-fill strong, unique passwords for all your accounts. Popular options include LastPass, 1Password, and Bitwarden.

Ensure that your master password for the password manager is exceptionally strong, as it protects all your other passwords.

4. Enable Multi-Factor Authentication (MFA)

MFA adds a crucial layer of security by requiring additional verification beyond just a password. Even if your password is compromised, attackers still need the second factor to access your account.

While SMS-based verification codes are common, they’re vulnerable to SIM swapping attacks. Use authenticator apps (like Google Authenticator or Authy) or hardware security keys for stronger protection when possible.

5. Regularly Monitor for Credential Leaks

Use services that alert you when your email appears in data breaches. These services scan known breach databases and notify you if your information is found, allowing you to take immediate action.

6. Practice Good Security Hygiene

• Change passwords regularly, especially for critical accounts
• Be cautious about phishing attempts in emails, texts, or phone calls
• Verify website authenticity before entering credentials (check for HTTPS and correct domain names)
• Use security questions with answers that aren’t easily guessable or findable online
• Keep your devices and software updated to protect against known vulnerabilities

Credential Monitoring Services

To stay ahead of credential leaks, consider using specialized monitoring services that can alert you when your credentials appear in data breaches or are being traded in private channels:

LeakJar: Provides comprehensive credential monitoring with access to over 60 billion pieces of compromised data. Their service can detect your leaked credentials before they reach the public dark web, giving you a critical time advantage. Try a FREE credential search with instant results; no signup is required to get an overview of your exposure.

What to Do If Your Credentials Are Compromised

If you discover or suspect that your credentials have been leaked:

1. Change your passwords immediately for the affected account and any other accounts where you’ve used the same or similar passwords
2. Enable MFA if it’s not already activated
3. Monitor account activity for any unauthorized transactions or changes
4. Check connected accounts that might be accessible through the compromised account
5. Consider credit monitoring or freezes if financial information was potentially exposed
6. Report the incident to the affected service and relevant authorities if financial fraud occurred

The Future of Credential Security

As attack techniques evolve, so too must our defense strategies. Passwordless authentication methods—using biometrics, hardware tokens, or one-time codes delivered through secure channels—are gaining traction as more secure alternatives to traditional passwords.

Gartner estimates that companies implementing Threat Exposure Management processes will see a 66% decline in Data Breach Risk by 2026. This approach focuses on continuous discovery, prioritization, and validation of exposures across the entire attack surface, including credential vulnerabilities.

Conclusion

Your credentials are valuable assets that require robust protection. Understanding how they can be compromised, the journey they take after being leaked, and the methods attackers use to exploit them is the first step toward better security.

By implementing strong password practices, using multi-factor authentication, and staying vigilant about potential security threats, you can significantly reduce the risk of becoming a victim of credential-based attacks. Remember that in cybersecurity, proactive protection is always more effective than reactive measures after a breach has occurred.

“80% of data breaches involve compromised credentials, and leaked credentials from unknown attacks can go undetected for months.”
Check Your Account Instantly — Fast, Free, and Easy!