How Credential Attacks Work and 5 Defensive Measures [2025 Guide]

What Are Credential Attacks? 

A credential attack is a security breach where unauthorized parties attempt to gain access to a system, network, or account using stolen, guessed, or brute-forced passwords. These attacks exploit vulnerabilities in authentication protocols or capitalize on weak user practices like password reuse. 

The primary goal is to infiltrate accounts and systems to steal sensitive information or commit fraud. Credential attacks are increasingly common due to the growing number of data breaches, exposing a significant volume of user credentials online. Such attacks often involve automated processes, making them efficient and scalable. Attackers may deploy bots to attempt thousands of logins rapidly, seeking vulnerable accounts. 

The ease of access to breached credentials on the dark web exacerbates the problem, as attackers can obtain passwords with minimal effort or cost. As users continue to utilize passwords across multiple platforms, the likelihood of successful credential attacks increases.

This is part of a series of articles about insider threat.

Recommended Reading: Security Big Data Analytics: Past, Present and Future.

The Impact of Credential Attacks 

Successful credential attacks pose severe risks to both businesses and customers.

Impact On Businesses

Credential attacks can lead to significant financial losses, damaged reputation, and compromised data integrity. Data breaches resulting from these attacks might expose sensitive corporate information or customer data, leading to regulatory fines and legal liability. The cost of remediation, alongside investments in improved security measures, can exceed initial estimations, affecting business operations and stakeholder trust.

Impact On Consumers

Consumers are particularly vulnerable to credential attacks, often facing personal and financial repercussions following unauthorized access to their accounts. Stolen credentials can lead to identity theft, unauthorized transactions, or loss of personal data, all of which can result in financial loss and emotional stress. Recovering from such events may require extensive time and effort, compounded by potential financial institution involvement.

How Credential Attacks Work 

Credential attacks typically follow a systematic process, leveraging various tools and techniques to exploit weak authentication mechanisms. The steps often include:

1. Credential collection: Attackers gather login credentials through phishing campaigns, social engineering, malware, or by purchasing leaked credentials from data breaches. The dark web and hacker forums serve as common marketplaces for acquiring such data.
2. Automated testing: Once credentials are collected, attackers use automation tools such as botnets to test them across multiple platforms. This process, often referred to as credential stuffing, targets accounts where users have reused passwords.
3. Brute-force attempts: For accounts not exposed through breaches, attackers may employ brute-force techniques to guess credentials. These involve testing numerous combinations of passwords systematically, often using software optimized to bypass basic security measures.
4. Exploitation: Upon successfully accessing an account, attackers may exfiltrate sensitive data, make unauthorized transactions, or use the account as a gateway to infiltrate larger systems. Compromised accounts can also be sold to other attackers for further exploitation.
5. Avoiding detection: Attackers use advanced evasion techniques such as rotating IP addresses, mimicking legitimate user behavior, and leveraging compromised devices to bypass traditional security measures. Static detection rules often fail against these methods since they rely on pre-defined conditions that attackers can anticipate. A more effective approach involves tracking behavioral deviations across multiple sessions and correlating them with risk-based scoring to detect anomalous account usage, unusual access locations, and deviations from normal login behavior.

Tips from the expert

Steve Moore is Vice President and Chief Security Strategist at Exabeam, helping drive solutions for threat detection and advising customers on security programs and breach response. He is the host of the “The New CISO Podcast,” a Forbes Tech Council member, and Co-founder of TEN18 at Exabeam.

In my experience, here are tips to effectively prevent and respond to credential attacks:

Enable account lockout policies strategically: Configure account lockout policies to prevent brute-force attacks. Use progressive lockouts or temporary delays after failed attempts to balance security with usability and prevent denial-of-service exploitation.

Implement adaptive multi-factor authentication (MFA): Rather than applying static MFA challenges, organizations should implement adaptive authentication that evaluates risk factors such as device type, user behavior, login frequency, and historical access locations. Anomalous login attempts—such as a sudden login from an unusual country or multiple failed attempts followed by a success—should trigger additional verification steps dynamically.

Deploy credential stuffing detection mechanisms: Use tools that identify and block patterns of automated credential testing, such as unusual login attempts from multiple IPs or repeated failed login attempts across accounts.

Enforce password hygiene with breach detection tools: Regularly check user passwords against known breached password databases using APIs or integrated tools like Have I Been Pwned. Automatically enforce resets for accounts with compromised credentials.

Segment access privileges for sensitive accounts: Apply the principle of least privilege (PoLP) to ensure sensitive accounts, like admin or financial accounts, have minimal permissions. Use access segmentation to reduce the impact of a compromised account.

Differences Between Credential Stuffing and Brute Force Attacks 

Credential stuffing and brute force attacks are both login exploits but differ in methodology. Credential stuffing relies on using pre-collected credential lists to achieve unauthorized access, while brute force attacks involve systematically trying all possible password combinations until the correct one is found. Credential stuffing is more efficient, leveraging the assumption of password reuse, making it less time-consuming than the resource-intensive brute force method.

Brute force attacks exploit vulnerabilities like weak passwords and lack encryption safeguards, taking substantial time and computing power. In contrast, credential stuffing attacks are executed swiftly due to the prior collection of leaked data. 

Organizations can counter credential stuffing with measures like rate limiting and monitoring login attempts, while thwarting brute force attacks requires implementing strong password policies and login delay mechanisms to hinder rapid incorrect password submissions.

Common Types of Credential Attacks 

Credential Harvesting

Credential harvesting involves collecting login credentials through deceptive means, often via phishing attacks or fake websites designed to mimic legitimate platforms. Attackers lure users into entering their usernames and passwords into these fake interfaces. Once harvested, these credentials can be used in direct attacks or sold on the dark web. 

The success of credential harvesting heavily depends on the attacker’s ability to convincingly disguise the malicious source. These attacks leverage social engineering techniques to bypass technical defenses, exploiting human weaknesses rather than system vulnerabilities. 

Credential Theft

Credential theft occurs when attackers directly obtain usernames and passwords through hacking, social engineering, or exploiting software vulnerabilities. Unlike credential harvesting, which often tricks users into willingly providing their credentials, credential theft can involve more aggressive tactics like installing keyloggers or exploiting network vulnerabilities. 

Once credentials are stolen, attackers can fully impersonate victims, leading to unauthorized data access and potential identity theft. Protecting against credential theft requires a strong security posture, including firewall implementations, intrusion detection systems, and regular software updates to patch known vulnerabilities. 

Credential Stuffing

Credential stuffing involves using automated tools to try out multiple username and password combinations on various websites to see if they give unauthorized access. This method exploits the tendency of people to reuse passwords across different accounts. Attackers start with a set of leaked credentials and test them on multiple platforms, banking on successful login attempts due to repeated password use. 

Credential stuffing is high-paced and can affect numerous accounts simultaneously, making it a potent threat. Automated credential stuffing allows attackers to perform these actions at scale. Once access is gained, attackers may deploy malware, launch additional attacks on internal resources, or sell the credentials to other malicious actors. 

Techniques Used in Credential Attacks 

Phishing and Social Engineering

Phishing and social engineering are prevalent techniques that manipulate individuals into divulging sensitive information. This manipulation involves deceptive communications, such as emails or messages that mimic legitimate sources, prompting users to enter credentials into fake portals. 

These tactics heavily rely on exploiting human psychology rather than technical vulnerabilities, often utilizing urgency or impersonation to increase success rates. Educating users about recognizing phishing attempts and maintaining skepticism toward unsolicited communications is crucial. 

Malware and Keyloggers

Malware and keyloggers are insidious tools used for credential theft. Malware disrupts or damages systems, often enabling unauthorized access to sensitive information, while keyloggers discreetly record keystrokes, capturing credentials as they’re entered. 

These tools can be distributed via malicious downloads, email attachments, or compromised websites, allowing attackers to harvest vast quantities of data stealthily. Defending against malware and keyloggers requires vigilant cybersecurity practices, including regular software updates, antivirus protection, and network defense mechanisms. 

Man-in-the-Middle Attacks

Man-in-the-middle (MitM) attacks intercept and alter communications between two parties, often to extract sensitive information like login credentials. Attackers position themselves between victim and endpoint, capturing data secretly. MitM attacks can occur on unsecured networks, such as public Wi-Fi, where traffic is unencrypted, making it accessible for interception. 

Attackers may inject malicious scripts or redirect users to spoofed sites during these interceptions. Countermeasures against MitM attacks include using HTTPS protocols to encrypt web traffic, ensuring secure connections. Implementing virtual private networks (VPNs) adds an additional encryption layer when accessing networks remotely. 

5 Ways to Prevent Credential Attacks 

Here are some of the ways that organizations and individuals can protect themselves against credential attacks.

1. Implement Multi-Factor Authentication (MFA)

Multi-factor authentication (bolsters account security by requiring additional verification steps beyond traditional passwords. This layered approach minimizes unauthorized access risks, as attackers must circumvent not just passwords but additional factors, such as biometric data or temporary codes sent to user devices. 

Implementing MFA can thwart many credential-based attacks, even when passwords are compromised. Organizations should mandate MFA across all platforms, enabling secure system access through various authentication methods like TOTP apps, SMS codes, or hardware tokens. Educating users about the importance of MFA and its implementation in routine security practices strengthens organizational resistance to credential breaches. 

2. Enforce Strong Password Policies

Strong password policies are fundamental in preventing credential attacks, emphasizing the use of complex, unique passwords for each account. Enforced policies often include requirements for length, character variety, and regular changes to minimize password vulnerability. Encourage users to avoid common phrases or predictable sequences, making it harder for attackers to guess or brute force access to accounts.

Supporting users with password creation tools and management solutions improves adherence to strong password policies. Conducting periodic audits to ensure compliance and providing guidance on secure password habits are crucial steps. 

3. Conduct Employee Security Training

Security training for employees is critical in defending against credential attacks, focusing on awareness, detection, and response strategies. Training sessions should encompass recognizing phishing attacks, understanding social engineering tactics, and protecting personal and organizational credentials. 

By fostering an informed workforce, organizations cultivate vigilance against evolving threats, reducing internal vulnerabilities. Regular workshops, simulations, and updates on emerging threats ensure employees remain equipped to handle security challenges. In a security-first culture, employees are proactive in reporting suspicious activities, strengthening defenses. 

4. Utilize Bot Detection and Mitigation Tools

Bot detection and mitigation tools identify and block malicious bots trying to access accounts through automated login attempts. They leverage various techniques, including behavior analysis and challenge-response tests, to distinguish human users from bots, reducing credential attack success rates.

Integrating bot management solutions within existing security frameworks allows organizations to monitor traffic and limit bot-driven access attempts. Implementing real-time analytics and automated response systems ensures rapid adaptation to evolving bot strategies. By embedding these tools, companies strengthen their resilience against automated credential exploits.

5. Monitor the Dark Web for Compromised Credentials

Dark web monitoring helps organizations detect compromised credentials before they are used in attacks. By scanning underground forums and marketplaces where stolen data is traded, security teams can identify exposed accounts and take proactive measures to mitigate risk. Detecting leaked credentials early allows for immediate action, such as enforcing password resets, restricting access, or triggering additional authentication steps to prevent unauthorized logins.  

To strengthen security, organizations should integrate dark web monitoring with real-time threat detection and response workflows. When a credential is flagged as compromised, security teams should automatically correlate it with recent login activity and behavioral patterns to determine if an account is already under attack. Continuous monitoring, regular security assessments, and automated response mechanisms help reduce the window of exposure and prevent attackers from exploiting stolen credentials.

Learn more in our detailed guide to compromised credentials 

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