#CredentialStuffing

When Strong Passwords Fail: Lessons from a Silent, Persistent Attack

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As an IT professional, I pride myself on maintaining robust security practices. I use unique, complex passwords, enable two-factor authentication (2FA), and regularly monitor my accounts. Despite these precautions, I recently experienced a security breach that served as a stark reminder: even the most diligent efforts can fall short if certain vulnerabilities are overlooked.

The Unexpected Breach

I maintain a Microsoft 365 Developer account primarily for SharePoint development. This account isn’t part of my daily workflow; it’s used sporadically for testing and development purposes. To secure it, I employed a 36-character random password—a combination of letters, numbers, and symbols. This password was unique to the account and stored securely.

Despite these measures, I received a notification early one morning indicating a successful login attempt from an unfamiliar location. Fortunately, 2FA was enabled, and the unauthorized user couldn’t proceed without the second authentication factor. This incident prompted an immediate investigation into how such a breach could occur despite stringent password security.

The Silent Persistence of Attackers

Upon reviewing the account’s activity logs, I discovered a disturbing pattern: months of failed login attempts originating from various IP addresses. These attempts were methodical and spread out over time, likely to avoid triggering security alerts or lockouts. This tactic, known as a “low and slow” brute-force attack, is designed to fly under the radar of standard security monitoring systems.

Such persistent attacks underscore the importance of not only having strong passwords but also implementing additional security measures. According to the Cybersecurity and Infrastructure Security Agency (CISA), 2FA is essential to web security because it immediately neutralizes the risks associated with compromised passwords. If a password is hacked, guessed, or even phished, that’s no longer enough to give an intruder access: without approval at the second factor, a password alone is useless .

The Vulnerability of Dormant Accounts

One critical oversight on my part was the assumption that an infrequently used account posed less of a security risk. In reality, dormant accounts can be prime targets for attackers. These accounts often retain access privileges but are not actively monitored, making them susceptible to unauthorized access. As noted by security experts, dormant accounts often fly under the radar, making them perfect targets for threat actors. Since they aren’t actively monitored, cybercriminals can exploit them for weeks—or even months—before being detected .

This realization led me to reassess the security of all my accounts, especially those not regularly used. It’s imperative to treat every account with the same level of scrutiny and protection, regardless of its frequency of use.

Immediate Actions Taken

In response to the breach, I took several immediate steps to secure the compromised account and prevent future incidents:

First, I changed the account’s password to a new, equally complex and unique one. Recognizing that the email address associated with the account might have been targeted, I updated it to a more obscure variation, reducing the likelihood of automated credential stuffing attacks.

Next, I thoroughly reviewed the account’s security settings, ensuring that all recovery options were up-to-date and secure. I also examined the activity logs for any other suspicious behavior and reported the incident to Microsoft for further analysis.

Finally, I conducted a comprehensive audit of all my accounts, focusing on those that were dormant or infrequently used. I enabled 2FA on every account that supported it and closed any accounts that were no longer necessary.

Lessons Learned

This experience reinforced several critical lessons about cybersecurity:

Firstly, password strength alone is insufficient. While complex passwords are a fundamental aspect of security, they must be complemented by additional measures like 2FA. According to research, implementing 2FA can prevent up to 99.9% of account compromise attacks .

Secondly, dormant accounts are not inherently safe. Their inactivity can lead to complacency, making them attractive targets for attackers. Regular audits and monitoring of all accounts, regardless of usage frequency, are essential.

Thirdly, attackers are persistent and patient. The “low and slow” approach to brute-force attacks demonstrates a strategic method to bypass traditional security measures. Staying vigilant and proactive in monitoring account activity is crucial.

Strengthening Security Measures

In light of this incident, I have adopted several practices to enhance my cybersecurity posture:

I now regularly audit all my accounts, paying special attention to those that are dormant or infrequently used. I ensure that 2FA is enabled wherever possible and that all recovery options are secure and up-to-date.

Additionally, I have started using a reputable password manager to generate and store complex, unique passwords for each account. This tool simplifies the process of maintaining strong passwords without the need to remember each one individually.

Furthermore, I stay informed about the latest cybersecurity threats and best practices by subscribing to security newsletters and participating in professional forums. This continuous learning approach helps me adapt to the evolving threat landscape.

Conclusion

This incident served as a sobering reminder that no one is immune to cyber threats, regardless of their expertise or precautions. It highlighted the importance of a comprehensive security strategy that includes strong passwords, multi-factor authentication, regular account audits, and continuous education.

I encourage everyone to take a proactive approach to cybersecurity. Regularly review your accounts, enable 2FA, use a password manager, and stay informed about emerging threats. Remember, security is not a one-time setup but an ongoing process.

If you found this account insightful, consider subscribing to our newsletter for more cybersecurity tips and updates. Share your thoughts or experiences in the comments below—we can all learn from each other’s stories.

D. Bryan King

Sources

Disclaimer:

The views and opinions expressed in this post are solely those of the author. The information provided is based on personal research, experience, and understanding of the subject matter at the time of writing. Readers should consult relevant experts or authorities for specific guidance related to their unique situations.

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Opalsec :verified:Opalsec@infosec.exchange
2025-04-05

Our latest post is out, check it out for the full details here 👉 opalsec.io/daily-news-update-s

If you're short on time, here's a quick rundown of the key stories:

🇦🇺 Australian Pension Funds Under Attack: A significant credential stuffing campaign hit multiple Aussie superannuation funds (Australian Super, REST, Hostplus, Insignia, ART) over the March 29-30 weekend. Attackers used stolen creds, likely targeting web portals and mobile apps, accessing accounts and unfortunately stealing funds in some cases (reports mention ~AU$500k from four Australian Super members alone). ASFA is coordinating the response. A stark reminder about password reuse and MFA effectiveness, especially during off-hours!

🏛️ Shake-up at NSA/Cyber Command: Big news out of the US – Gen. Timothy Haugh has been fired from his dual-hat role leading the NSA and USCYBERCOM after just over a year. Deputy Director Wendy Noble is also reportedly out. Reasons are murky, but speculation points towards political motivations (linked to Laura Loomer's visit with President Trump). This raises questions about stability, the ongoing 'Cybercom 2.0' review, and the future of the dual-hat structure, especially with ongoing nation-state threats.

⏱️ Incident Response Speed vs. Backups: An interesting debate highlighted recently – while backups are vital for recovery, is rapid IR potentially even more critical? It’s a tough balancing act: contain fast (risking tipping off attackers/losing evidence) or investigate thoroughly while the breach continues? Emphasises the need for skilled responders and adequate tooling, not just relying on backups as a silver bullet.

⚠️ Critical RCE in Apache Parquet (CVE-2025-30065): Heads up, data folks! A CVSS 10.0 RCE vulnerability has been found in the widely used Apache Parquet columnar storage format (up to v1.15.0). Given its use in Hadoop, AWS, Azure, GCP, and by major tech companies, the potential impact is huge. Patch to version 1.15.1 ASAP!

📱 Pentagon Probes Defense Secretary's Signal Use: The DoD's Inspector General is investigating Defense Secretary Pete Hegseth's use of Signal for official business. This follows a report where a journalist was accidentally added to a Signal chat discussing sensitive airstrike details (targets, timing). Raises concerns about classified info on unclassified apps, need-to-know, and record-keeping compliance.

The full blog post dives deeper into each of these stories and much more. Don't forget to sign up to our newsletter so you can get this daily wrap-up straight to your inbox!

📨 opalsec.io/daily-news-update-s

What are your biggest takeaways from this week's news? Let's discuss below!

#CyberSecurity #InfoSec #ThreatIntel #DataBreach #CredentialStuffing #Ransomware #Phishing #Vulnerability #ApacheParquet #NSA #CyberCommand #IncidentResponse #CloudSecurity #NationalSecurity #Espionage #Privacy

2025-04-04

Cybercriminals have exploited simple password reuse to drain AUD 500K from Australian pension funds. Is your retirement savings secure? Read on to uncover the vulnerabilities.

thedefendopsdiaries.com/cyber-

#cybersecurity
#credentialstuffing
#australianpensionfunds
#cyberattacks
#multifactorauthentication

Cyber Tips Guidecybertipsguide
2025-03-17

Cybersecurity Alert - New AI agents like OpenAI's Operator can amplify credential stuffing attacks. Implement robust MFA & stay informed to protect your digital identity.

Learn more - zurl.co/OSdAX

Steve Ragan (SteveD3) :verified:SteveD3@infosec.exchange
2024-12-19

Not sure who is playing around, but I don't use my Proton Mail account for things like this.

#credentialstuffing

An image from Keeper Security stating that: "A request has been received to login to Keeper with a new device, but a Keeper account with this email does not exist."
2024-12-04

Credential Theft is on the Rise! Our CPO Dan Featherman shares the inside scoop on infostealer malware, password spraying, brute force, and credential stuffing attacks, as well as how they are used to break into accounts and sensitive systems. lmgsecurity.com/the-insiders-g

#CyberSecurity #BruteForce #CredentialStuffing #IT #infostealermalware

2024-11-15

The complexity of the passwords I am seeing in this #credentialstuffing attack is depressing. Apparently we’ve learned nothing. #infosec

Prof. Dr. Dennis-Kenji Kipkerkenji@chaos.social
2024-07-08

#RockYou2024: Wohl bislang größter #Passwort #Leak - #Achtung an alle, die ihre #Passwörter wiederverwenden oder dasselbe Passwort für den gleichen Dienst nutzen! #CredentialStuffing

"Höchstwahrscheinlich enthält die neueste RockYou-Version Informationen aus über 4.000 Datenbanken, die man über mehr als zwei Jahrzehnte zusammengetragen hat. In der Zukunft muss man mit vielen weiteren Datenlecks rechnen."

tarnkappe.info/artikel/cyberan

2024-06-12

Battered and bruised 23andMe faces probe after hack that stole seven million users’ data - 23andMe, the California-based company which sells DNA testing kits to help people learn a... bitdefender.com/blog/hotforsec #credentialstuffing #databreach #guestblog #lawℴ #dataloss #23andme #dna

2024-05-06

Jako bych na to nedávno neupozorňoval u #credentialstuffing.
Příliš často recyklujeme hesla. A tady píší, že si je navíc někde poznamenáváme.
Což nemusí být úplně špatně, pokud je bezpečně zaznamenáte ve správci hesel.
Ať tak nebo tak, recyklace hesel je špatně a samotná hesla stejně nestačí.
techradar.com/pro/security/a-s

gtbarrygtbarry
2024-05-05

Okta warns of "unprecedented" credential stuffing attacks on customers

Okta warns of an "unprecedented" spike in credential stuffing attacks targeting its identity and access management solutions, with some customer accounts breached in the attacks

bleepingcomputer.com/news/secu

Marcus "MajorLinux" Summersmajorlinux@toot.majorshouse.com
2024-04-22

Time to mix up those passwords!

Roku hit by credential stuffing attack - Desk Chair Analysts

dcanalysts.net/roku-hit-by-cre

#CredentialStuffing #InfoSec #MFA #Passwords #Roku #Tech #DCA

"Roku hit by credential stuffing attack" text laid over the Roku logo.

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