Credential Harvesting: What It Is, How It Happens And How To Prevent It

While cybercriminals have many sophisticated ways to infiltrate business systems, one of the most effective is also the most direct: logging in with stolen credentials. Rather than breaking through firewalls, attackers use valid usernames and passwords to slip past defenses unnoticed, essentially walking through the front door rather than hunting out any hidden access points.

According to Verizon’s 2025 Data Breach Investigations Report, credential abuse is the initial access vector in 22 percent of confirmed breaches. This makes it the number one source of entry to business networks, ahead of vulnerability exploitation (20 percent) and phishing (16 percent).

There are many ways attackers can source the credentials they need, from phishing and fake login portals to malware, leaked databases and dark web marketplaces. This process, known as credential harvesting, is often the first step in a broader attack chain. Once attackers gain access, they can quietly escalate their privileges, exfiltrate sensitive data or deploy ransomware, often without triggering any alarms.

Credential harvesting is the process of collecting usernames, passwords and other authentication details. Attackers use a variety of methods to trick individuals into handing over login credentials, from social engineering to spyware.

Cybercriminals may harvest credentials for different reasons. In some cases, the goal is direct access to key systems or sensitive data such as financial records, intellectual property or email accounts. In others, the stolen information is used for identity theft or sold in bulk on dark web marketplaces.

Attackers commonly target credentials tied to email accounts, cloud services, internal portals, customer databases or admin tools. However, obtaining these details is rarely the end goal. Credential harvesting is often the first step in a wider attack chain that includes privilege escalation, data exfiltration, lateral movement and, eventually, ransomware deployment.

Credential harvesting doesn’t always require advanced technical skills. Many attacks rely on human error, poor digital hygiene, misplaced trust or psychological manipulation. Cybercriminals often exploit moments of carelessness to gather the details they need, using familiar-looking prompts or silent background tools to capture credentials. Some of the most common methods include:

• Phishing emails: Fake messages that prompt users to reset passwords or log in to bogus services. Today’s efforts – often enhanced by AI – are more convincing than ever at persuading users to hand over information.
• Spoofed login portals: Lookalike web pages that mimic legitimate services and capture usernames and passwords as users attempt to sign in.
• Keyloggers: Malware silently installed on devices such as employee laptops or smartphones that records every keystroke, including login credentials.
• Man-in-the-middle attacks: Intercepts data between the user and legitimate websites. The use of services like unsecured public Wi-Fi can often leave users vulnerable to this.
• Malicious browser extensions or third-party apps: Tools disguised as helpful software – and often obtained from legitimate app stores – that siphon credentials in the background.

These techniques are widely used because they are proven to work, especially when employees aren’t trained to spot the signs. Therefore, it’s vital employees are aware of them and take steps to avoid them.

Harvested credentials are a powerful asset for cybercriminals because they offer direct, undetected access to critical systems. Once inside, attackers can move freely across networks, install ransomware and exfiltrate sensitive data without triggering alerts. Stolen logins also allow fraud, such as unauthorized wire transfers, payroll manipulation or accessing customer records.

In many cases, credentials are reused across systems, giving criminals even broader access. Beyond the immediate breach, these credentials are often sold on the dark web, where access to business tools, email accounts or cloud platforms can enable further attacks, espionage or identity theft.

Effective, real-time network monitoring is essential for identifying the misuse of stolen credentials before serious damage is done. While credential theft often goes unnoticed initially, there are several red flags that may indicate an account has been compromised. These include:

• Unusual login times or access from unfamiliar locations.
• Multiple failed login attempts, followed by success.
• Unrequested multifactor authentication prompts.
• Access to systems or files outside a user’s normal role.
• Unauthorized changes to email forwarding or security settings.
• Reports of suspicious messages sent from a user’s account.

Employees play a critical role in preventing credential harvesting. While technical defenses matter, human behavior is often the first line of defense. However, with human error being a leading cause of data breaches, there’s clearly work to be done in any organization. Training can only go so far, as every staff member must take personal responsibility for following secure practices and staying alert to potential threats.
Key steps all users should follow include:

• Using strong, unique passwords for every account.
• Storing passwords in a trusted password manager, not in browsers or unsecured files.
• Enabling multifactor authentication wherever available.
• Avoiding clicking login links in emails. Instead, they should navigate directly to trusted sites.
• Double-checking URLs before entering any credentials.
• Reporting suspicious activity immediately, even if it turns out to be a false alarm.

Even well-trained employees can make mistakes. At the same time, sophisticated threats like AI-powered spear phishing make it easier for even vigilant staff members to fall victim. Therefore, businesses can’t rely on individuals alone.

To minimize the risk, organizations need layered, proactive defenses that detect, block and contain credential-based attacks at every level. These solutions help build a strong safety net, protecting businesses even when people get it wrong.

• Email security gateways that block phishing and spoofed login pages.
• Endpoint detection and response (EDR) to flag keyloggers and info-stealing malware.
• DNS filtering to prevent users reaching malicious credential harvesting sites.
• Anti data exfiltration (ADX) to prevent stolen credentials or other sensitive data obtained using such accounts from leaving the network.
• Real-time monitoring and access control to detect unusual behavior fast.