If you’re in cyber security, you’re used to big, dramatic attack headlines, but sometimes, the biggest threat is a login someone reused in 2018.

Credential-based attacks are surging in both frequency and sophistication. This blog breaks down what they are, why they’re growing so fast, and what needs to change.

What Is a Credential-Based Attack?

It’s exactly what it sounds like: attackers use stolen or leaked login credentials, usually email + password combos, to gain access to systems, data, and tools.

Most of the time, it looks like:

• Credential stuffing: trying known leaked credentials across multiple sites
• Password spraying: using common passwords against known usernames
• Account takeover (ATO): accessing legitimate accounts for lateral movement or fraud

These attacks often don’t raise red flags. There’s no malware, no phishing link, no malicious file. Just someone logging in… with the correct details.

The Reality Check

This isn’t a minor threat.

• In early 2025, over 1.7 billion stolen credentials were circulating on the dark web (SpyCloud)
• Credential-based attacks increased 42% year-over-year globally (TechRadar, May 2025)
• 86% of web app breaches involved stolen credentials (Verizon DBIR 2024)
• The average company experiences 1,300 credential-stuffing attempts per month (IBM Security)

It’s not just happening to giant corporations, either. SMEs, startups, and even individual freelancers are on the radar, especially those using popular SaaS tools without strong authentication.

Why It’s Getting Worse

This problem isn’t new, but several things are making it worse:

• Massive breach reuse: Every new breach adds millions of credentials to the pool, and most people still reuse passwords.
• Sophisticated bots: Credential stuffing is automated now. Tools like Snipr and OpenBullet test thousands of logins per second across services.
• Low-cost access: Stolen credentials are cheap. Full account logins for Google, Microsoft 365, or AWS go for under $10 on some forums.
• MFA isn’t a magic bullet: Multi-factor authentication helps, but not all MFA is equal and attackers are now phishing or proxying MFA tokens, too.

Where These Attacks Lead

Once logged in, attackers can:

• Harvest internal documents, code, and client data
• Move laterally into other systems
• Create new users or persistence mechanisms
• Launch vendor impersonation scams
• Use the access to phish other employees or customers

In addition to being an IT issue, it poses a business, brand, and legal risk.

What Companies Should Be Doing

• Stop relying on passwords. Seriously. Use passkeys or passwordless logins where possible. At a minimum, enforce strong, unique passwords with a password manager.
• Implement adaptive MFA, basic SMS-based 2FA isn’t enough. Use app-based or hardware tokens and require reauthentication based on risk signals (like location or device changes).
• Monitor for leaked credentials - use threat intel platforms or breach monitoring services to get alerts when your domain or employee emails show up in leaks.
• Teach people how attackers exploit login reuse. Include real examples, not generic “don’t click this” slides.
• Enforce least privilege. Limit account access to only what’s needed. If a credential is compromised, it shouldn’t open every door.

Final Thoughts

Credential attacks are often thought of as “unsophisticated”, but they’re actually smart, efficient, and increasingly automated. And in a world where everyone uses cloud tools, logins are the new perimeter.

If you haven’t reviewed your identity and access management this year… you’re behind. Might be time for a little spring cleaning, don’t you think?