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What is a Compromised Credentials Attack?

by Alexa Sander on December 19, 2024

The education industry is among the most highly targeted of all sectors. K-12 schools are particularly at risk, given the vast amount of sensitive information they hold. Out of all forms of cyberattacks, compromised credentials attacks are among the most pernicious — often with long-lasting effects.

How can K-12 schools best strengthen their security posture to prevent compromised credentials attacks? Read on as we cover this, and more.

Compromised credentials attack: What is it?

A compromised credentials attack occurs when an unauthorized individual gains access to valid login information — such as usernames and passwords — and uses it to infiltrate systems. Rather than relying on sophisticated vulnerabilities in software or hardware, these attacks exploit the human element — often leveraging easily guessed passwords, leaked credentials, or data from previous breaches. Once attackers have access, they can move freely within the environment and gain access to sensitive data.

For K-12 schools, compromised credentials attacks are an increasingly pressing concern. Educational institutions store a range of data, from student health records and financial information to various other personal details. When this information falls into the wrong hands, it can lead to identity theft, financial fraud, reputational harm, and other long-lasting consequences for students, their families, and the institutions entrusted with keeping their data secure.

Common causes of compromised credentials

A variety of factors contribute to compromised credentials and, in the context of K-12 schools, several unique challenges come into play. One of the most common causes is weak or reused passwords. Students, teachers, and administrators may rely on simple, easy-to-remember passwords or recycle the same credentials across multiple platforms. This practice greatly increases the risk of unauthorized access — if a single password is leaked, it can potentially unlock numerous accounts.

Phishing attacks also pose a significant threat to K-12 schools. This is where cybercriminals craft emails or messages that appear to originate from trusted sources, encouraging recipients to enter their login details on fraudulent websites. With the rapid shift to online learning tools, many school staff and students receive a constant stream of emails from unfamiliar platforms, making it harder to distinguish legitimate requests from malicious ones

In addition, data breaches at third-party vendors that handle school information can result in large-scale credential leaks. If a service that stores login information or manages school software is compromised, attackers can harvest usernames and passwords en masse. In some cases, attackers even utilize automated scripts or bots to attempt credential stuffing — trying sets of leaked credentials across multiple accounts to find a match.

Technical misconfigurations and lax access controls can further exacerbate the problem. Without proper identity and access management (IAM) in place, users may retain access to sensitive systems even after they no longer need it — increasing the attack surface.

What are the risks of a compromised credentials attack?

For K-12 schools that encounter a compromised credentials attack, the most immediate and serious risks involve unauthorized access to sensitive data. This could include personally identifiable information, academic records, health-related details, and financial documents. Once cybercriminals obtain valid credentials, they can navigate systems with ease, often going undetected for extended periods. During this time, they can collect and exfiltrate confidential information, leading to a range of potential fraudulent activities and harm to a student’s long-term financial and academic well-being.

Beyond data theft, these attacks can disrupt school operations. Unauthorized users might tamper with grade books, attendance records, or even online testing platforms — undermining the trust between students, faculty, and administrators. Plus, the subsequent recovery process can be lengthy and costly, requiring significant resources to restore systems and rebuild security measures. Additionally, the reputational damage inflicted on a district or institution can be challenging to overcome, potentially eroding community confidence in the school’s ability to safeguard its digital assets.

SingularityMD uses compromised credentials to attack school districts

In late October 2023, the same criminal group responsible for breaching Clark County School District in Nevada — a collective calling itself “SingularityMD” — turned its attention to Jeffco Public Schools in Colorado. By exploiting a student account protected only by the student’s date of birth as a password, the attackers gained a foothold in Jeffco’s network. From there, they navigated through the district’s systems, benefiting from weak configurations and improperly shared resources in Google Drive and Google Groups.

Once inside, the attackers claim to have harvested a wide range of sensitive data, including staff contact details, confidential financial documents, and outdated backup files. Perhaps most concerning was their reported access to student records and Individualized Education Programs, which included personal information like names, birthdates, emergency contacts, and other private details. The group then demanded a $15,000 ransom in the cryptocurrency monero, threatening to publicly release all stolen data, contact affected families directly, and involve the media if their demands were not met.

This case highlights the alarming consequences of compromised credentials in a K-12 setting. A single weak password opened the door to a broad infiltration, resulting in the potential exposure of private student and staff information. Beyond the risk of identity theft and financial fraud, the district now faces reputational harm, possible legal actions, and a significant investment of time and resources to restore trust, bolster security measures, and prevent future breaches.

Preventing compromised credentials attacks: 5 key strategies for K-12 schools

While compromised credentials attacks will continue, there are practical steps that K-12 schools can take to mitigate and reduce the impact of these threats.

Implement multi-factor authentication (MFA)

Multi-factor authentication fortifies access to critical systems by requiring multiple verification steps, such as a one-time code, biometric scan, or security token — in addition to traditional passwords. This extra layer minimizes the risk that compromised credentials, stolen passwords, or exposed credentials can be used to infiltrate accounts.

Enforce strong password policies

Establishing rigorous password policies helps deter credential compromise before it starts. K-12 schools should mandate complex, unique passwords that are regularly updated and never reused, which in turn limits password reuse vulnerabilities. Such measures hamper brute force attacks and credential-based attacks, preventing compromised accounts from cascading into more extensive data breaches. Moreover, schools should consider automated checks to detect weak credentials and provide clear guidelines to staff and students.

Conduct regular training

Continuous, targeted cybersecurity training empowers the entire school community — faculty, administrators, and students alike — to recognize and resist cyber threats. Effective programs highlight the warning signs of credential attacks, educate users on safe practices to prevent credential theft, and emphasize the dangers of password reuse.

Adopt robust access controls

Effective IAM practices ensure that only authorized individuals access sensitive information. By assigning roles, privileges, and restrictions based on functions, schools can better prevent attackers from freely moving within their systems using compromised credentials. Additionally, implementing strict access controls reduces the impact of exposed credentials, effectively thwarting credential stuffing attacks and containing incidents of credential compromise.

Leverage account takeover and phishing detection tools

Advanced detection solutions can automatically identify abnormal login patterns, suspicious behavior, and phishing attempts before they escalate into successful credential attacks. These tools spot anomalies like multiple failed logins, unusual geolocations, and unusual account activities.

Cloud Monitor does just that, plus more. With Cloud Monitor, schools gain continuous visibility into unusual login behavior and unauthorized access attempts across Google Workspace and Microsoft 365. It instantly flags suspicious activity, initiates automated remediation actions, and ensures sensitive data remains protected — all without the need for complicated setup or specialized training.