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Cactus Ransomware
Under attack by ransomware or suffering a cyber breach?
Speed is critical when facing a live cyber attack. If you believe you’ve been compromised, by the Cactus ransomware group or another threat actor - contact us immediately.
About Cactus ransomware group
Cactus Ransomware was first observed in March 2023 and is believed to have roots in Russia. The Cactus ransomware group is said to be one of the fastest-growing threat groups of 2023.
An infection with Cactus is characterised by your systems displaying a ransom note, with the specialist cyber crime group holding your infected machine, systems, and stolen sensitive data hostage until a ransom is paid. Victims often discover that personal files and login credentials have been compromised and access controls removed.
What we can help with:
- Encrypted files & ransomware data recovery
- Incident response and containment
- Secure data restoration and system recovery
- Use of ransomware decryption tools and data recovery software
- Development of incident response plans and disaster recovery solutions
- Post-incident reviews and security hardening
Request a call back
If your organisation has been infected with ransomware contact us immediately.
How Cactus operators work
Cactus first emerged in 2023, reusing the TotalExec.ps1 script originally associated with the Black Basta ransomware group, indicating a possible link or evolution from the original Black Basta threat actors.
Cactus employs advanced techniques to gain initial access, often by exploiting known vulnerabilities or purchasing stolen credentials. These threat actors are known to use legitimate tools, similar remote access software, remote assistance, and social engineering tactics to manipulate users into granting unauthorised access, often evading traditional threat detection mechanisms. Believed to have links to the Black Basta group, the operators behind Cactus remain highly active, continually adapting their methods to compromise target networks and maximise impact.
Once inside a network, they exfiltrate sensitive data before encrypting files on targeted systems, leaving behind a ransom demand. This double-extortion tactic is designed to pressure organisations into paying not only for the decryption key but also to prevent public disclosure of the stolen information.
We are equipped to deal with an attack from any ransomware group.
Don’t hesitate to contact us if you are under attack from a ransomware group not listed above.
Recognising a Cactus attack
Cactus attacks are technically ground-breaking. Their malicious activity, including lateral movement, remote access, and layered social engineering, allows them to evade detection and stay hidden within compromised systems for weeks. These attack chains methods often begin with phishing or vulnerability exploitation, followed by stealing data before deploying a ransomware binary. The tactics used by Cactus suggest links to certain threat actors, demonstrating a high level of sophistication and persistence.
To maintain persistent control, Cactus operators frequently establish backdoors and use scheduled tasks or legitimate tools to ensure continued access even after partial remediation efforts.
Double extortion is a nefarious tactic used by cybercriminals to amplify the impact and urgency of their demands. In such a scheme, perpetrators not only encrypt the victim’s data but also threaten to release or sell it if their ransom demands are not met.
Why you must not interfere with your ransomware environment
If you discover a physical break-in at your offices, your first instinct would be to call the police; touch nothing and let them search for clues. Then, your focus would shift to restoring business operations.
A cyber-attack requires the same approach. Your digital environment is a CRIME SCENE. It is crucial to leave the environment untouched to allow for a forensic investigation.
This is not a task for your IT team or MSP. Digital Forensic specialists are available 24/7 to assist you, just like in a physical crime.
Known threat actors
Ransomware groups behind the attacks
Below is a breakdown of the most active ransomware groups and the variants driving their attacks.
Post breach actions
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Call a NCSC Cyber Incident Response approved supplier Some NCSC providers will fund up to 48 hours of investigation into your incident.
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Report the incident to Report Fraud
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Locate your business continuity plan Work out what you can do without access to your systems and data.
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Identify your business insurance contact details
Who are we and what experience do we have in responding to cyber incidents?
We are accredited to ISO 27001 and recognised by the UK’s National Cyber Security Centre (NCSC).
We provide comprehensive cyber risk management services, with a core focus on Digital Forensics and Incident Response (DFIR). Our capabilities are driven by a 24/7 Security Operations Centre and a dedicated in-house intelligence team that delivers timely, actionable threat reporting.
With decades of collective cyber security experience, we have the expertise to assume operational ownership of your entire IT security architecture – simplifying and strengthening cyber security across your business.
As an Assured Service Provider for Cyber Incident Response (CIR) at the Standard Level. This accreditation demonstrates our ability to deliver high-assurance, effective support in response to a wide range of cyber threats.
Your NCSC-approved supplier is a specialist crime scene investigator who will:
- Isolate and preserve your environment for forensic investigation.
- Identify where the data has been duplicated and issue a legal takedown order.
- Identify your data, application and systems restore points. These might be at different points in time and will need to be carefully restored and reconstructed in a pristine environment.
- Liaise with your business insurance company and if needed, with the Police.
- Advise you on notifying your customers of your situation.
- Rebuild your systems, restore your data and get you back to full operation. Note: This process can take between 2 weeks – 2 months.
Working with us
Our response process
Our team are ransomware recovery specialists with a proven, streamlined approach to resolving incidents quickly and effectively.
Step 1: Triage
We deploy our incident response team the same day. From the first call, we begin onboarding, introduce key stakeholders, set communication schedules, and start gathering critical information to guide the response.
Step 2: Investigation
DFIR (Digital Forensic Incident Response) teams investigate breaches to identify vulnerabilities, attack vectors, and system impacts from ransomware such as Data Loss (PII). We deliver clear forensic insights to guide mitigation.
Step 3: Contain
Our onsite and remote teams act fast to stop the attack in its tracks. That includes isolating affected systems, removing malicious code, and putting protections in place to prevent further spread or damage.
Step 4: Remediate & Eradicate
Once contained, we work to fully eliminate the threat. This includes fixing exploited vulnerabilities, restoring systems to a secure state, and ensuring no traces of the attack remain.
Step 5: Recover
Our incident response teams help get your business back to normal. We restore access to systems, recover data, and ensure services are safe, stable, and functioning, with minimal downtime.
Step 6: Post Incident
We conduct a full review of the incident response and recovery efforts. Together we assess what happened, what worked, and what can be improved, helping you build stronger defences for the future.
Forensic analysis to drive recovery
Our process includes a thorough digital forensic analysis from step two where the output becomes a central component of business recovery. This is because understanding the attack is of critical importance:
Informing an initial infection date
The extent and spread of infection
Data exfiltration having an impact on regulatory positions
Ensuring that the attacker and any tooling or artefacts they leave behind are eradicated
It is critical that the analysis of digital evidence is carried out to an agreed plan.
Maximising early root cause discovery and legal leverage
The process is purpose-built to uncover the root cause as early as possible, which is essential to inform remediation / eradication and recovery as well as supporting a legal take-down case if this is applicable. A legal take-down means we can assist in the legal enforcement that stops the criminals from publishing the data, thus undermining the ransom notice.
Our Digital Forensic and Incident Response (DFIR) teams maintain consistent communication throughout. Dedicated Incident Managers and technical engineering leads provide updates during the Cyber Incident Response journey, utilising risk registers and working within change management processes, all from triage through to post-incident, delivering successful business recovery.
Key take aways
- You will not be able to access your systems or data.
- It is advised to disconnect from the internet and shut down your systems, including PCs, to prevent further infections.
- Your Office 365 system might also be compromised, allowing the attackers to monitor your responses. Avoid communicating with individuals through your primary email or team systems.
- Threat actors typically infiltrate your system at least 2-4 weeks before you become aware of the attack. Your data will have already been exfiltrated. If your system is encrypted, this was not an overnight event.
- Ransom demands in the UK typically range from £500,000 to £3 million, with some sectors, like education, facing demands that exceed £5 million
- Paying the ransom may violate financial sanctions, which is a criminal offence and could result in a custodial sentence or further financial penalties.
- If your data is sold or published online, it puts your customers and staff at risk, potentially implicating you in a Data Protection breach.
- You will need to submit a data takedown request to the initial location where the data was transferred.
- Do not overwrite the encrypted data. It is crucial to determine when the infection began and where the data was sent.
- Avoid rebuilding from the latest backup, as it is likely to be infected.
Why should I trust Zensec to do this work rather than my IT team?
A forensic analysis needs to be meticulous and a clean restore and recovery requires a wealth of experience not normally available in an in-house team who must provide a broader range of IT support skills:
Internal IT teams don’t have the necessary skill set to resolve security encryption issues themselves.
IT teams may recover to the same position with indicators of compromise ready to do it again… which can lead to another breach.
Internal teams are pressured to restore business operations and may recover before forensic analysis even begins, potentially destroying the crime scene before completion.
We can help
Frequently asked questions
Key information when you’re under pressure.
Yes, Cactus is a type of ransomware, and the group behind it operates under a Ransomware-as-a-Service (RaaS) model. This means they develop and sell their malicious code to affiliates, who then carry out ransomware attacks independently.
Cactus operators are known for exploiting remote assistance tools and other legitimate software to infiltrate networks, often blending their activity with normal enterprise workflows to evade detection. This level of sophistication presents significant challenges for traditional defences, making proactive security measures, such as threat hunting, behavioural monitoring, and zero-trust architecture, crucial in mitigating risk.
The Cactus ransomware likely entered your system through one or more common attack vectors:
Phishing attacks
Exploiting known vulnerabilities
Purchasing stolen credentials
Failing to maintain software updates
Abuse of remote control capabilities or remote assistance usage
To reduce the risk of future infections, we strongly recommend adopting the following robust cyber security measures:
Educate staff on the importance of cyber security awareness
Enforce the use of strong, unique passwords
Implement multi-factor authentication (MFA) across all systems
Regularly review and remove inactive or unnecessary user accounts
Perform frequent, tested backups
Apply timely updates to software, operating systems, and security tools
After recovering from a Cactus ransomware incident, Zensec advises updating your business continuity plan to reflect lessons learned during the attack and recovery process. This ensures your organisation is better prepared for future threats and capable of responding swiftly and effectively.
A ransomware attack presents the most significant threat to your business by:
- Disabling your access to systems, which could hinder machinery operation or impede progress through your business processes.
- Blocking access to critical data concerning suppliers, shipments, customers, orders, or steps in your business workflow.
In the event of a business interruption, identifying your position in the supply chain and sustaining operations can be challenging. If the disruption continues, maintaining business continuity becomes critical. Once systems and data are restored, addressing backlogs and establishing future operational protocols are essential.
Ransomware ranks only behind receivership in terms of its capacity to incapacitate a business.
The NCSC is the UK National Cyber Security Centre. They provide cyber security guidance and support, helping to make the UK the safest place to live and work online. They have defined a Cyber Incident Response procedure and they have approved and accredited suppliers to provide this service.
As a recognised Assured Service Provider by the National Cyber Security Centre (NCSC), Zensec provide comprehensive cyber risk management services that are designed to Protect, Detect & Mitigate cyber security threats across the UK.
Report Fraud is the UK's national reporting centre for fraud and cybercrime. Whether you have been scammed, defrauded, or experienced cybercrime in England, Wales, or Northern Ireland, Report Fraud offers a central point of contact for information on fraud and financially motivated cybercrime.
https://www.reportfraud.police.uk/https://www.actionfraud.police.uk/
Most ransomware breaches cost approximately £500K, while smaller email data breaches typically cost around £50K. There is a critical balance between preserving the environment for forensic analysis and quickly recovering it to minimise business interruption. The costs increase the longer it takes to identify and resolve the breach.
A cyber security insurance claim is complex, covering reasonable expenses for investigating and remediating an incident, along with legal fees, business interruption, criminal liability, employment liability, and ransom payments. Although the insurance industry is responsible for facilitating business recovery, cyber insurance is viewed as volatile, and many policies are not being validated correctly.
Finding your way through demands expertise, and that's where Zensec can offer assistance.
Yes. There's a possibility that some of the lost data falls under the category of "Personal Data" belonging to your customers. It's your legal responsibility to safeguard this data, even if it has been lost. Additionally, you may need to notify the Information Commissioner's Office at https://ico.org.uk/.
Your insurer or legal counsel will provide guidance on the necessary steps and how to move forward in this situation.
Zensec has experience collaborating with insurers and legal professionals and can offer support in managing this relationship during this challenging period.
Dealing with a ransomware attack?
Our ransomware recovery service can help
Our expert team works quickly to contain the breach, recover your data, and restore your systems to full operation. We’ll guide you through every step of the recovery process and help strengthen your defences to prevent future attacks. Regain control with Zensec - trusted support when it matters most.