Skip to content
Chaos Ransomware Decryption and Recovery
Under attack by ransomware or suffering a cyber breach?
Speed is critical when facing a live cyber attack. If you believe you have been compromised by the Chaos ransomware group or another threat actor, contact us immediately.
About Chaos ransomware group
Chaos ransomware is a ransomware variant that has circulated in multiple forms since 2021. It is often associated with relatively unsophisticated but highly disruptive ransomware attacks, where ease of access and speed of execution are prioritised over stealth or long-term persistence.
The Chaos group, or individuals using Chaos-based tooling, have targeted a wide range of organisations across different industries, including government entities and commercial businesses. Chaos has been used both by independent threat actors and as a base for modified ransomware variants, contributing to inconsistent tactics and capabilities across incidents.
Early versions of Chaos showed minimal historical activity, but newer Chaos ransomware variants demonstrate faster encryption speeds and selective encryption of targeted files, reflecting an evolving threat landscape.
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 Chaos operators work
Initial access is commonly achieved through weak or reused passwords, exposed internet-facing services, phishing emails, or voice phishing. In some incidents, attackers have exploited victim internet-facing services such as remote access tools, including Microsoft Quick Assist.
Once access is gained, attackers may enumerate domain user accounts, scan network resources, and deploy the ransomware rapidly across compromised machines. Chaos ransomware performs selective encryption, often targeting large or sensitive files based on file size and extension rather than encrypting entire systems.
Encryption is carried out using AES encryption, with individual file encryption keys generated during the encryption process. In many cases, limited effort is made to uninstall security tools or evade detection, indicating lower operational maturity compared to more advanced ransomware families.
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 Chaos attack
A Chaos ransomware attack is typically identified by encrypted files, targeted file extensions, and the appearance of a Chaos ransomware ransom note containing payment instructions and victim communication details.
Organisations may observe rapid encryption across Windows machines, compromised victim machines entering Windows recovery mode, or files being permanently deleted if encryption fails. In some incidents, attackers have conducted repeated attacks against the same environment where security controls remain weak.
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
-
Call a NCSC Cyber Incident Response approved supplier Some NCSC providers will fund up to 48 hours of investigation into your incident.
-
Report the incident to Report Fraud
-
Locate your business continuity plan Work out what you can do without access to your systems and data.
-
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.
Chaos ransomware is a malware family used by various threat actors to conduct ransomware attacks. It encrypts data on victim systems and issues ransom demands in exchange for a private key required for decryption.
Chaos ransomware targets specific file extensions associated with large or sensitive files. This selective encryption approach allows the ransomware to encrypt data quickly while maximising operational and data confidentiality impact.
File extensions are used to identify which files should be encrypted. Chaos ransomware may skip system files while focusing on documents, databases, and other valuable data within the victim’s environment.
The Chaos ransomware ransom note typically includes ransom demand details, payment instructions, and a victim communication channel. Some notes reference double extortion messaging, warning of data leaks if payment is not made.
The Chaos ransomware builder is a tool that allows attackers to generate customised ransomware payloads. This builder enables configuration of file extensions, encryption behaviour, ransom note structure, and selective encryption options.
New Chaos ransomware variants demonstrate faster encryption speeds, improved selective encryption, and broader cross-platform ransomware software capabilities compared to early versions.
Chaos functions as both a ransomware builder and a base ransomware framework. It is not always operated as a formal ransomware-as-a-service programme, but its builder tooling allows multiple actors to conduct repeated attacks.
Risk reduction measures include multi factor authentication, strong password policies, securing internet-facing services, monitoring PowerShell event logs, regular security testing, and maintaining reliable backup software to support system recovery.
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.