In 2019, the cybersecurity landscape was rocked by a data breach at Citrix. Threat actors managed to extract sensitive business files from a shared network directory and a drive linked to a web-based tool used by Citrix’s consulting unit. The intrusion was traced back to a password spraying attack – a method that takes advantage of weak password hygiene. The incident drew widespread criticism, with experts blaming the company’s inadequate password security policies for unnecessarily jeopardizing client data.
Citrix is hardly an outlier in this regard. When a cybersecurity research team analyzed Microsoft user accounts in early 2019, they found that 44 million users were still using credentials that had previously been exposed in unrelated data breaches.
Although password spraying attacks can’t be fully avoided, they can be identified and thwarted. This article explores the mechanics of such attacks, signs that indicate an attack in progress, and measures you can implement to reduce your exposure to these threats.
What Is a Password Spraying Attack?
Traditional brute force attacks bombard a single account with a wide range of password attempts. Modern systems are generally equipped to detect this abnormal activity and respond with account lockouts after repeated failed login efforts.
Password spraying inverts this tactic. Instead of trying numerous passwords on one account, attackers test one commonly used password across a large pool of user accounts. They then repeat the process with a second password, and so on. This technique allows attackers to sidestep typical lockout policies and extend the duration of their attempts.
The effectiveness of password spraying stems from the prevalence of poor password practices. In 2019, analysis of breached credentials revealed that many users still relied on simple combinations such as “12345,” common given names, or even the word “password.” Attackers leveraging a broad list of common credentials and targeting many accounts inevitably gain access to some.
Today’s attackers often adopt more targeted approaches. They frequently go after users who rely on single sign-on (SSO) systems, aiming to compromise credentials that unlock multiple applications and environments. Cloud service users and systems using federated authentication are also prime targets. Federated authentication, in particular, can obscure malicious behavior and facilitate lateral movement across systems.
Once attackers gain access, compromised accounts can result in data leaks, loss of intellectual property, or service disruptions. For organizations, the impact can be even more far-reaching – damaging operations, eroding customer trust, and incurring financial loss.
Identifying a Password Spraying Attack
Conventional defense mechanisms may not immediately catch password spraying attempts, but there are reliable indicators. A notable one is a surge in login attempts – especially failed logins due to incorrect passwords – in a compressed time frame. Spikes in account lockouts are often a related indicator.
Another warning sign is an abnormal increase in authentication attempts via SSO portals or cloud-based services. Adversaries typically use automated scripts to flood systems with login attempts, sometimes thousands at a time. These requests may originate from the same IP address or endpoint.
Preventing and Minimizing Exposure
Timely detection is crucial, but even a brief window of unauthorized access can cause serious damage. That’s why a proactive, defense-in-depth security model is essential. Here are some best practices to adopt:
- Implement multifactor authentication (MFA) for all users.
- Define secure password reset procedures to follow account lockouts.
- Apply strict password policies for all shared or generic accounts.
- Train users regularly to understand the risks of password spraying and follow strong password practices.
How Netwrix Can Help
To effectively protect against password spraying, organizations should consider deploying security tools that combine real-time detection with thorough auditing and alerting capabilities.
Netwrix Auditor is designed to notify you of abnormal behavior, including events that suggest a password spraying attempt. It provides detailed audit trails and flexible alerting features that help you react quickly and decisively. Key functionalities include:
- Comprehensive Active Directory monitoring – The tool tracks all logon activity, including both failed and successful attempts. Administrators can configure alerts for specific actions, such as privilege elevation, or activity patterns, like more than four failed logins in a minute. Full session history is also available for review.
- User behavior analytics (UBA) – Netwrix Auditor ranks risk actors based on behavior and gives a consolidated view of anomalies, enabling faster identification of compromised or malicious users.
- Detection of hidden threats – The platform flags suspicious behavior such as logins during off-hours, multiple users logging in from a single endpoint, or a single user accessing systems from multiple locations.
Additionally, Netwrix Auditor helps harden your environment against attacks by improving visibility and control:
- Monitor password policy adherence and get alerts on configuration changes.
- Track Azure AD password changes to secure cloud environments.
- Identify accounts lacking passwords or with passwords that never expire.
- Detect and deactivate dormant accounts before attackers can exploit them.
In essence, Netwrix Auditor equips you to detect threats early and proactively reduce your organization’s attack surface – making it much harder for adversaries to succeed.
