Password spraying is a cyberattack where attackers attempt to gain unauthorized access to multiple accounts using a single common password. Unlike brute-force attacks that target one account with numerous guesses, password spraying targets many accounts with a few common passwords. This helps attackers avoid account lockout mechanisms, which activate after multiple failed attempts, and exploits weak password practices, as many users choose simple, easy-to-guess passwords.

How does Password Spraying Work?

In a password spraying attack, the process begins with attackers acquiring a list of usernames. These lists can be obtained through various means, such as purchasing from data breaches, scraping public information, or using common corporate email formats. Once the attackers have a comprehensive list of potential targets, they compile a set of commonly used passwords, often derived from studies, reports, or previous breaches.

With both lists in hand, attackers proceed by attempting to log in to each account using one password at a time. This methodical approach allows them to avoid triggering account lockout mechanisms, which are typically activated after multiple failed login attempts on a single account. By spreading out the attempts across many accounts, they can remain under the radar of security systems designed to detect brute-force attacks.

Automation plays a crucial role in the efficiency of password spraying. Attackers often use automated tools to systematically iterate through the username and password combinations. This not only speeds up the process but also increases the likelihood of finding a match, as the tools can quickly test a large number of credentials without manual intervention.

What are Examples of Password Spraying?

Real-world examples of password spraying attacks highlight the significant impact this method can have on organizations. In early 2024, Microsoft disclosed that accounts from its legal, executive, and cybersecurity teams had been breached using password spraying. This attack was attributed to the Russian state-backed group Midnight Blizzard, which had previously performed the SolarWinds attack of 2020. The hackers compromised a legacy test account and used it to gain access to senior leadership accounts.

Another notable instance involved the Iranian state-backed threat actor Peach Sandstorm, which launched cyberespionage attacks between February and July 2023. These attacks targeted defense, satellite, and pharmaceutical organizations, using password spraying as a central technique to establish persistence and collect intelligence. These examples underscore the diverse range of industries and high-profile targets that can fall victim to password spraying attacks.

What are the Potential Risks of Password Spraying?

The potential risks of suffering a password spraying attack are significant and multifaceted. Here are some of the key risks:

• Financial Losses: Unauthorized access can lead to financial damage through fraudulent transactions, theft of financial data, or selling sensitive information to competitors.

• Reputational Damage: Data breaches resulting from password spraying can severely harm an organization's reputation, leading to loss of customer trust and potential declines in stock prices.

• Operational Disruptions: Compromised systems can disrupt daily operations, causing delays, canceled transactions, and significant recovery times that can last weeks or even months.

• Legal Consequences: Failing to protect user data can result in legal repercussions, including fines and sanctions under data protection laws and regulations.

• Increased Vulnerability: Once initial access is gained, attackers can use the compromised accounts as a gateway for further, more damaging attacks, such as phishing or ransomware.

How can you Protect Against Password Spraying?

Protecting against password spraying requires a multi-faceted approach. Here are some key strategies:

• Enforce Strong Password Policies: Require complex passwords that include a mix of letters, numbers, and special characters. Regularly update these policies to adapt to evolving threats.

• Implement Two-Factor Authentication (2FA): Adding an extra layer of security ensures that even if passwords are compromised, unauthorized access is still prevented.

• Monitor Login Activity: Continuously track login attempts to identify unusual patterns that may indicate a password spraying attack.

• Set Account Lockout Policies: Establish thresholds for failed login attempts to temporarily lock accounts, making it harder for attackers to succeed.

• Use CAPTCHA: Implement CAPTCHA challenges to thwart automated login attempts by bots.