Os ataques de ransomware estão longe de desacelerar. No último ano, foram registradas 11.796 vítimas diretas desse tipo de ciberataque ao redor do mundo, 1,3 vítimas por hora, segundo dados do BTTng da Apura Cyber Intelligence, plataforma de inteligência em ameaças cibernéticas. O impacto vai além dos números: empresas paralisadas, serviços essenciais comprometidos e milhões de pessoas expostas a riscos iminentes.

A onda de ataques abrange qualquer empresa de todos os segmentos, desde a saúde até os serviços públicos. Em maio passado, a Ascension Healthcare, uma das maiores operadoras de saúde dos EUA, foi alvo de um ataque cibernético que comprometeu sistemas críticos, incluindo registros médicos e comunicação interna. Hospitais ficaram sem acesso a informações essenciais por semanas, forçando equipes a recorrerem a procedimentos manuais. “Isso gerou riscos reais, com erros relatados no Kansas e em Detroit, que poderiam ter resultado em graves consequências médicas”, explica Anchises Moraes, Especialista de Theat Intel da Apura.

A Ascension não divulgou oficialmente o grupo por trás do ataque, mas investigações apontam para o Black Basta. Sete dos vinte e cinco mil servidores foram comprometidos, e 5,6 milhões de indivíduos receberam notificações sobre o possível vazamento de dados.

No Brasil, a TOTVS foi alvo do grupo BlackByte, com relatos de que dados da empresa foram acessados. A companhia informou seus acionistas, garantindo a continuidade dos serviços, mas sem dissipar completamente a incerteza. Já a Sabesp sofreu um ataque do grupo RansomHouse, que não apenas roubou dados, mas também os publicou posteriormente.

O futuro dos ataques: alvos menores, impactos maiores

Se antes os criminosos miravam grandes corporações exigindo valores exorbitantes, a tendência é que ataques menores, porém em massa, ganhem força em todo o mundo, incluindo o Brasil. Pequenas e médias empresas se tornaram alvos fáceis, já que possuem menos recursos para segurança e maior propensão a pagar resgates. “Elas têm mais dificuldade em recuperar dados roubados ou encriptados, tornando-se presas ideais para esses criminosos”, alerta Anchises.

The BlackBasta ransomware group’s leaked chat logs have proven to already be another unique and fascinating opportunity for researchers to better understand the internal operations of a Russia-based organised cybercrime enterprise. These leaks followed a major leak of Conti chat logs in 2022, which also proved to be a treasure trove of intelligence on the cybercrime enterprise. The BlackBasta gang consists of former Conti ransomware members and it should come as no surprise that their operations are similar in nature and structure.

Ransomware researchers have several valuable resources to conduct investigations with nowadays. This includes ransomware.live, which contains several resources including ransomch.at, a collection of negotiation chats between ransomware gangs and their victims, as well as the ransomware tool matrix and ransomware vulnerability matrix. These resources allow to deeply understand the capabilities and motivations of these ransomware gangs. However, leaked chat logs are the final missing piece of the puzzle and offer a deeper understanding from the cybercriminal’s very own perspective and organisational structure.

Active since April 2022, BlackBasta is one of the top-tier ransomware gangs and one of the largest cybercrime enterprises in the world. According to the US Cybersecurity Infrastructure and Security Agency (CISA), BlackBasta impacted up to 500 different businesses and critical infrastructure in North America, Europe, and Australia as of May 2024.

The importance of the Ascension Health incident

This blog shall dive deep into the Ascension Health attack by BlackBasta. It is a step-by-step extraction of the conversation between the BlackBasta members while they decide how to handle the attack.

The new insights around how BlackBasta and other ransomware gangs perceive being involved with incidents at healthcare sector victim should prove useful for incident responders, law enforcement, and governments that have to resolve these types of attacks on the healthcare sector on an alarmingly regularly basis.

Background

On 9 May 2024, mainstream news organisations in the US reported about a cyberattack and significant disruption of services of Ascension Health, one of the largest healthcare providers in the country. On 11 May 2024, BleepingComputer reported that BlackBasta was to blame for the attack on Ascension Health and that ambulances had been disrupted and patients were being redirected to other hospitals.

How the Incident Began

The BlackBasta attack on Ascension Health began many months before the ransomware was deployed on their network. Reconnaissance of Ascension Health by members of BlackBasta began around 3 November 2023. They shared 14 email addresses of Ascension Health employees, which we can only assume were used for phishing or password guessing. Ransomware gangs often used Zoominfo to profile their targets to determine whether it is worth it for them to attack and get a ransom from them.

The ransomware gang themselves wrote in their Matrix chat that CBS News had written about a cyberattack on Ascension Health on 9 May 2024 and exclaimed that “it looks like one of the largest attacks of the year.”

Another BlackBasta member “gg” confirmed in the chat that it was them and appeared to be surprised that the news was writing about it.

Later, “gg” appeared to feel bad about the attack and concerned that cancer patients were suffering. However, at this stage it is hard to tell if they are serious or being sarcastic.

One member of BlackBasta who used the moniker “tinker” then stated that he wanted to be the negotiator for the BlackBasta team and began to strategize how to extract a ransom payment.

“gg” says they encrypted Ascension Health’s network using the Windows Safe Mode Boot technique, which is a function that BlackBasta is well-known to do.

The negotiator, “tinker” begins to weigh up their options. He states he believes the FBI and CISA will be involved, as well as Mandiant and begins to compare the incident to the Change Healthcare attack by ALPHV/BlackCat (and later RansomHub) who received a 22 million USD ransom payment.

“gg” shares that all the stolen data was put on a server named “ftp8” and tagged as “ALBIR_DS” and says to “tinker” that he should “look at the folder name, everything we downloaded from them is there."

The operator, “gg” also shared a summary of the target environment of Ascension Health. This includes number of servers being over 12,000, what security tools they use such as Cylance, Tanium, and McAfee. Plus, “gg” said they downloaded over 1.4TB of data to "ftp8" and used BlackBasta ransomware version 4.0 and attacked them on 8 May 2024.

Interestingly, “gg” appears to have also recommended to bluff to the victim that they stole more than 1.5TB and say to the victim that they stole 3TB instead.

Negotiation Strategizing

After having established the details of the incident, Tinker (the negotiator) began to wonder about the likelihood of getting a ransom payment as well as estimate how much Ascension Health is likely losing per day.

Tinker (negotiator) then explains to the rest of the BlackBasta members involved in the attack what course of action they should take to get the ransom from Ascension Health. Tinker says they would normally set a 3% of the annual revenue and negotiate from there. They note that there are clear problems with the victim being a hospital and that this attack followed the Change Health attack by ALPHV/BlackCat. They also noted that they are worried as they believe the US National Security Agency (NSA) attacked TrickBot's servers four years ago and that the FBI took down Qakbot more recently. Tinker is  also worried that one of Ascension Health’s patients will die and they will be blamed and labelled as a terrorist attack.

Tinker also noted that when BlackSuit attacked Octapharma that it was labelled by the news as "hostile actions by Russia" and they warned that Conti was already under sanctions and that because they are tied to Conti they may not get paid.

Tinker, ransomware negotiator for BlackBasta, ultimately recommended giving the decryptor for free to Ascension Health and resorting to data theft extortion. This is notable, as it is a similar situation to the Irish HSE ransomware attack by Conti, who also provided the decryptor for free.