Credential Theft: How attackers steal credentials and how to prevent it
Credential theft has always been an effective way to maliciously breach a network. The normalization of SaaS, cloud, and other remotely accessible resources is causing a shift in how attackers plan, approach, and market their efforts.
Instead of breaking into systems through complex exploits, attackers are increasingly logging in using stolen usernames and passwords, making their activity harder to detect and easier to execute.
Small and medium-sized businesses (SMBs) are especially attractive targets for credential-based attacks. Many SMBs operate with limited IT resources, fewer security layers, and inconsistent enforcement of best practices like multi-factor authentication (MFA) or least privilege access.
This creates an environment where a single compromised password can open the door to critical systems, sensitive data, and even full network control.
The scale of the problem is intensifying. Industry reports consistently show that a significant percentage of breaches now involve compromised credentials, often obtained through phishing, malware, or password reuse.
Other recent reporting has underscored the breadth of the issue, including warnings that stolen credentials are involved in roughly 60% of financial cyberattacks. As attackers continue to refine these methods, credential theft remains a low-effort, high-reward strategy.
In this article, we’ll break down what credential theft is, explain why compromised credentials are so dangerous, and examine the most common attack methods. Most importantly, we’ll outline practical steps to protect your organization from credential-based attacks.
What is credential theft?
Credential theft is the malicious act of stealing authentication credentials to access a system. Usernames, passwords, and these days, MFA codes are what most people think of when they define “credentials.”
Acting as the keys to the front door of virtually every remotely accessible service, resource, web frontend, or endpoint, they are valuable assets to attackers and unfortunately, easily compromised.
What qualifies as credentials can go beyond just a username and password. In some attacks, the goal is not to steal the password itself, but the session cookie or token issued after login. After successful authentication with a username, password, or other secret, proof of this authentication is provided in the form of a cookie or token that can be used to impersonate the user without re-entering credentials.
Why credential theft is so dangerous
What makes credential theft so dangerous is the virulent combination of three factors:
- How much easier it is to access a network or resource when you can simply log into it.
- How trivial it is to acquire valid login credentials.
- How much damage a single compromised account can cause, especially if it’s for a critical IT system.
Why go through the trouble of hacking into a network when you can just log into it? Stealing credentials is far easier than devising an attack that exploits technical vulnerabilities. So much so that 22% of the breaches assessed in Verizon’s 2025 DBIR used compromised credentials as the initial access vector.
The threat of credential theft continues to increase in parallel with the explosion of SaaS, cloud, and other remote-access front ends that serve as gateways into enterprise networks.
Stealing access to a user account usually requires additional reconnaissance and navigation of the victim’s network to find and access other resources. The ubiquity of remotely accessible portals and frontends has taken the guesswork out of finding these critical systems. The recent remote wiping of more than 80,000 endpoints across Stryker’s corporate network shows how destructive compromised access to these systems can become.
Other reasons contributing to the dangers of credential theft include:
Impersonation with tokens
Cookies, OAuth tokens, SAML assertions for SSO, and other such tokens all qualify as credentials that, if compromised, can allow an attacker to simply bypass submitting a username, password, and even MFA methods, assuming an authenticated session has already been established. If attackers capture a token through malware or phishing attack, they may be able to impersonate a legitimate user throughout an already-established network session by providing the token as proof of authentication.
Detection avoidance
It’s a lot harder to detect malicious activity when it’s performed with legitimate user credentials. That means many of their actions can blend in with normal account activity, especially if they are using valid credentials, approved devices, common SaaS apps, or stolen session tokens.
Even with EDR and other advanced security controls, defenders may see the activity as normal unless they are specifically watching for unusual behavior like logging in from an impossibly faraway place, accessing systems not typically used by that user, unusual privilege escalation attempts, or abnormal use of legitimate tools.
Identity-Based Expansion
Credential theft gives attackers a trusted foothold that lets them perform reconnaissance, enumerate users and systems, and move through the environment with far less suspicion than malware or exploit-based activity.
For instance, if the attacker compromises a user’s email account, they may also gain access to one-time passcodes, reset links, and other authentication messages used to complete MFA-protected logins. This allows the attacker to access resources beyond the compromised email account, turning it into a pathway for lateral movement and follow-on attacks.
Common methods of credential theft
Phishing and social engineering attacks
By far the most successful method, phishing and social engineering attacks rely on deception rather than technical exploitation. Instead of hacking their way in, attackers trick employees into revealing passwords, approving MFA prompts, or simply handing over access through fake emails, login pages and websites, text messages, or phone-based vishing scans.
The advent of AI-powered research and writing tools continues to make phishing emails more convincing than ever, duping even the most hawkeyed users.
Malware and infostealers
Malware-based credential theft happens when malicious software is installed on a device and quietly collects authentication data. This can include typed passwords, saved browser credentials, and cookies and tokens recorded in-transit from open network sessions.
Buying already stolen credentials
Not all attackers steal credentials themselves. Many simply buy, trade, or reuse credentials that were stolen by someone else and published in breach dumps, combo lists, or underground marketplaces.
One such recently discovered illicit database was found to contain over 149 million usernames and passwords acquired through a variety of methods, showing evidence that some credentials were stolen with info-stealing malware.
Stolen credentials not only give attackers access to your system, but in the case of databases housing millions of stolen credentials, credential stuffing becomes a worry.
Credential stuffing is a cyberattack method where attackers use automated tools to input many username and password pairs across multiple websites in the hopes of gaining access and taking over accounts on a large scale.
How to protect your organization against credential theft
Implement the following security controls and principles to keep your organization’s user and service account credentials secure.
Limit where users can login from
Where possible, configure your organization’s SaaS, cloud, and other remotely accessible resources to only accept authentication credentials when sent from specific IP addresses and network locations.
Even with stolen credentials, an attacker won’t be able to access a system that demands login attempts originate from a specific address.
Deploy best practice controls
Old fashioned tried and true security controls can still go a long way in limiting the effectiveness of a compromised user account. There’s no excuse for SMBs with limited resources when most of these practices are free:
- Strong least privilege principles can stop a user account from accessing all but the few tools and resources they need to perform their jobs. Remove local admin rights where they’re not needed, and limit access to tools and applications to the teams that need them.
- Enable MFA features already built into SaaS tools and other applications.
- Disable password reuse, either on each individual endpoint or on the network’s device management system (like Microsoft InTune), if one is available. If a user’s credentials have been swept up in a breach, reset it immediately.
- Phishing training courses are still an effective way to get the signs and dangers of credential theft across to users, even when modern phishing attacks almost guarantee an eventual successful compromise.
Implement phishing-resistant MFA
Small businesses can better protect against credential theft by implementing phishing-resistant MFA, such as FIDO2 security keys, because it prevents users from authenticating to fake sites and is far more resistant to phishing and info-stealing attempts.
NFC-enabled MFA devices extend that protection to mobile users as well, allowing supported iPhones and other NFC-capable devices to use the same hardware-backed authentication without using a stealable code.
Enable user account audit logging
Organizations should enable, and regularly review, access logs for signs of identity abuse, such as failed login spikes, logins from unusual locations, impossible travel, unexpected after-hours access, or normal users authenticating to systems they do not usually use.
Paying closer attention to both admin and user login activity helps identify patterns of misuse to catch compromised accounts earlier and contain suspicious access before it spreads.
Mitigate credential theft with ThreatLocker
Stolen credentials don’t have to automatically spell doom for a network. Organizations can prevent the damage of successful credential theft by implementing these Zero Trust controls in their network environment and prevent attackers from using the credentials they’ve stolen.
Zero Trust cloud access (ZTCA)
Login attempts to SaaS and cloud applications can be limited to specific endpoints, computer groups, users, and even applications with ThreatLocker ZTCA policies. By routing login attempts through a secure broker, policies can be written to permit or deny login attempts from any entity that isn’t already approved, making stolen credentials useless.
Zero Trust Network Access (ZTNA)
Organizations can extend the capabilities of the secure broker to individual network connections between endpoints. Remote access to another computer or server does not have to mean allowing access to the entire network through a VPN connection.
Like ZTCA policies, ZTNA policies permit network traffic over specific ports between specific addresses, users, and applications over a TLS encrypted session with configurable expiration limits and schedules.
See these capabilities in action and learn how to limit the blast radius of stolen credentials in our webinar: How to stop cybercriminals, even after credential theft.
