Blog Post October 12, 2023

A Threat Actor’s Playbook: 2023 Cyberattacks on Caesars Entertainment and MGM Casinos

By: Max Bernal, Technical Content Writer, and Adlumin’s Threat Research Team

A Threat Actor’s Playbook: 2023 Cyberattacks on Caesars Entertainment and MGM Casinos is a part of Adlumin’s Threat Bulletin Series content series.

In early September 2023, Caesars Entertainment in Las Vegas experienced a major cyberattack. The threat actors used a combination of social engineering tactics and ransomware to breach the casino’s networks and steal sensitive data. On September 10, another gambling conglomerate, MGM Resorts International, experienced a cyberattack by threat actors in the ALPHV ransomware-as-a-service (RaaS) group. The two attacks cost the casinos millions of dollars in losses.

Caesars Entertainment Cyberattack

Caesars Entertainment’s SEC filing on September 7, 2023, stated that it had suffered a social engineering attack “on an outsourced IT support vendor used by the company.” The exact date of the cyberattack was not disclosed, nor who carried out the assault.

In the filing, Caesars also stated that the cyberattack did not impact customer-facing operations like slot machines, guest services, and other services but that among the data stolen, the threat actor(s) had acquired a copy of the loyalty program database, which included member driver’s license and Social Security numbers.

Caesars also disclosed that it had taken steps to “ensure that the stolen data [was] deleted,” alluding that it had paid a ransom. Numerous news outlets, including Bloomberg, reported that the company paid “tens of millions of dollars.”1 Other news outlets, including CNBC, reported that Caesars paid $15 million.2

The company did not provide specific details on how the social engineering attack was carried out or identify the cybercriminal(s) by name. However, numerous news reports published statements from sources “familiar with the matter” that pinned the attacks on a hacker group called Scattered Spider, also known as “Scattered Swine,” “Muddled Libra,” and UNC3944 (by Mandiant), which is likely affiliated with the ransomware group, ALPHV.

The threat actor group is known for its sophisticated social engineering techniques and the ability to target and bypass Okta login security services.

MGM Resorts International Cyberattack

On September 12, 2023, MGM Resorts International issued a statement via PR Newswire stating that it had “identified a cybersecurity issue affecting the company’s systems.”3 MGM also stated that it had notified law enforcement to help protect networks and data, including by “shutting down certain systems.”

According to the Associated Press, MGM began experiencing disruptions on Sunday, September 10,4 and its reservations website was down that day. Soon after, numerous other media outlets reported that slot machines were out-of-service or were displaying errors across MGM-owned casinos, including at the MGM Grand, Bellagio, Aria, Mandalay Bay, Delano, Cosmopolitan, New York-New York, Excalibur, and Luxor. In addition, it was reported that thousands of guests had to wait in long lines for hotel check-ins and that credit card point of sales systems were down, forcing guests to pay cash.5

However, some of the same news outlets published statements from unvetted sources citing that the attack on MGM was carried out by the “same threat actors” that attacked Caesars Entertainment, Scatted Spider. On September 14, the ransomware-as-a-service (RaaS) group ALPHV issued a rare statement claiming sole responsibility for the attack and condemned news media and cybersecurity firms for publishing “false” and “unsupported” details on the attack.

“The ALPHV ransomware group has not before privately or publicly claimed responsibility for an attack before this point. Rumors were leaked from MGM Resorts International by unhappy employees or outside cybersecurity experts prior to this disclosure. Based on unverified disclosures, news outlets decided to falsely claim that we had claimed responsibility for the attack before we had,” part of the statement read. “Tech Crunch & others: neither you nor anybody else was contacted by the hacker who took control of MGM. Next time, verify your sources more thoroughly, or at the very least, give some hint that you do.” 

In an earlier version of the statement, ALPHV had also distanced itself from the Twitter/X account, “vx-underground,” which had published a post on September 12 stating that the attack was carried out by looking up employee information on LinkedIn and that a 10-minute phone call to the company’s help desk was all it took to “defeat” the multi-million-dollar company.

Numerous news media erroneously believed the threat actors had published the post to explain how they gained access to the MGM networks and used it in their reporting.  

1. Screen capture of the 9/12/2023 post published by vx-underground.

At some point, ALPHV removed the reference to “vx-underground” and issued another update:

“As of September 16, 2023, we have not spoken with journalists, news organizations, Twitter/X users, or anyone else. Any official updates are only available on this blog. You would think that after the tweet below, people would know better than to believe anything unreliable they would hear about this incident. If we talk to a reporter, we will share it here. We did not and most likely won’t,” ALPHV wrote.

The Adlumin Threat Research Team cannot confirm what tactics ALPHV used to break into MGM servers nor provide more details on the attack until MGM discloses what transpired.

According to ALPHV’s statement, the group was able to deploy ransomware once inside MGM’s network, encrypting about 100 ESXi hypervisors at the onset of the attack. The group also alluded to targeting the casino’s Okta services.

MGM operations resumed normal customer-facing operations on September 20. According to news reports, MGM lost about $8 million each day its servers were down, which adds up to $40 million.6

Adlumin contacted MGM for more details on the attack, but the company only referred us to their original September 12 statement.


How to Protect Yourself from Social Engineering


In Caesars Entertainment’s case, a simple vishing tactic, where a cybercriminal attempts to obtain information via phone call, was used to impersonate a legitimate employee and request a password reset. How? While the exact details are still unclear, we can surmise that personally identifiable information (PII) was obtained by the threat actors and used to reset an account.

An organization’s IT or cybersecurity department should verify an individual’s identity using information that cannot be found on social platforms, such as a unique company-issued ID, and not just a full name and date of birth, for example. If the individual calling can provide you with all the correct information, you may need to think outside the box; what are the circumstances surrounding this issue? Is the caller experiencing the issue they’re asking about? For example, if the caller asks for a password reset due to an ‘account lockout,’ you should verify that the account is locked out before proceeding with assistance. Most organizations have a form of internal communications platform used for employee-to-employee messaging and the like. Some organizations even have a call roster with the employee’s personal number. Therefore, give the employee a quick call to verify that the individual is contacting you.


Training is the most crucial defense against social engineering tactics. With incidents happening daily, remaining vigilant is essential. However, mere vigilance is not enough; frequent proactive security awareness training is vital to mitigate this type of threat. By consistently providing training, users gain a deeper understanding of the risks and measures to counter social engineering attacks.

This continuous education keeps cybersecurity at the forefront of their minds, ensuring they are better equipped to identify and respond to potential threats. Employing various training techniques and approaches helps to reinforce key principles and enhance overall cybersecurity proficiency among users. By prioritizing proactive cybersecurity awareness programs, organizations can establish a culture of security awareness and significantly reduce the propensity for successful social engineering attacks.

How Adlumin Can Help Protect Your Organization

Proactive Security Awareness: Adlumin offers a managed Proactive Security Awareness Program, which, as stated previously, is the best defense to counter social engineering tactics. Adlumin will develop and run monthly customized phishing simulations to educate and equip your users on how to identify phishing attempts. Learn more here.

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