149 lines
9.6 KiB
Markdown
149 lines
9.6 KiB
Markdown
Also see:
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- [Mitigation steps for businesses](https://www.nomoreransom.org/en/prevention-advice-for-businesses.html) from the Europol [No More Ransom project](https://www.nomoreransom.org/nl/index.html).
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- [Nationaal Cyber Security Centrum](https://www.ncsc.nl/onderwerpen/ransomware)
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See also:
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- [a-5.30-ICT-readiness-for-business-continuity](../Standards/ISO27x/OST/27002/EN/a-5.30-ICT-readiness-for-business-continuity.md)
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- [BCP_Bedrijfscontinuïteitsplanning](../📚️%20Literature%20notes/BCP_Bedrijfscontinuïteitsplanning.md)
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- [Disaster Recovery Planning](ISMS/Disaster%20Recovery%20Planning.md)
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3 Phases:
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- Prevention
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- During the attack
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- After the attack
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# Prevention
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- Identify specific techniques attackers are using [A 5.7](../Standards/ISO27x/OST/27002/EN/a-5.7-Threat-intelligence.md)
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- Workforce education
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- Remove vulnerabilities / Attack surface reduction
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- Business Continuity Planning (BCP)
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- Ransom payment policy
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## Workforce education
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[ISO 27002 A 6.3](../iso27diy-corp/Corpus/Standards/ISO-27002-OST/ISO27002-EN-2022/ISO_27002_2022_6.3_OT%20Information%20security%20awareness%2C%20education%20and%20training.md)
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Education programs should address the following:
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- Use caution when opening links or attachments by considering:
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- Do I know the sender?
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- Does this look suspicious?
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- Is this something that I should open or a link I should follow?
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- Use a Virtual Private Network (VPN) to gain the benefits of implemented security controls.
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- Do not provide personal details when answering emails, phone calls, texts, or other messages,
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- Contact the IT department as soon as possible if you receive suspicious communication.
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- Validate IT resources and communications to ensure communications from new contacts are not an attempt at social engineering.
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- Alert the IT department before traveling internationally.
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See also the [Guidelines for Regular Users](https://www.nomoreransom.org/en/prevention-advice-for-users.html) from the Europol No More Ransom project.
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## Attack surface reduction
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**Backup and restore**
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- Regularly back up your systems, online and offline. Up to date backups are the most effective way of recovering from a ransomware attack.
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- Ensure that you create offline backups that are kept in a different location (ideally offsite), from your network and systems, and/or in a cloud service designed for this purpose.
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- Perform tests on the critical information restoring process
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**Coverage**
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- Periodically check your coverage (know what you are *not* monitoring) as part of your vulnerability management (VM) program [A 8.8](../Standards/ISO27x/OST/27002/EN/a-8.8-Management-of-technical-vulnerabilities.md)
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- Identify critical information assets
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- Store sensitive data in compartmented locations.
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- Ensure that critical assets are isolated through network segmentation [A 8.22](../Standards/ISO27x/OST/27002/EN/a-8.22-Segregation-of-networks.md)
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**Testing and plugging for vulnerabilities**
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- Regularly run penetration tests
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- Scan for vulnerabilities in installed software
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- Scan your operating systems
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- See that all software is up to date and available patches are installed [A 8.8](../Standards/ISO27x/OST/27002/EN/a-8.8-Management-of-technical-vulnerabilities.md)
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- Know indicators of ransomware and block them from executing (e.g. by scanning mails for executable attachments)
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- Disable the execution of email attachments
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- block malicious websites, applications, protocols, etc. through content inspection
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- Implement blacklisting/whitelisting rules based on live threat intelligence feeds
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- Use anti-spear-phishing software that inspects links and attachments at the mail server
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- Keep antivirus and anti-malware products up to date
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- Disable scripting and macro's (e.g. MS Office macros)
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- preventing activation of OLE packages in Microsoft Word
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- Disable Windows PowerShell
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- Use RDP (Remote Desktop Protocols) only when absolutely necessary, and then only with MFA
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- Block access to high-risk category websites (adult material, games, gambling, advertisements, peer-to-peer file sharing)
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- Monitor data exfiltration: many ransomware campaigns come with the threat of releasing data to encourage businesses to pay the ransom
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- Implement measures such as hard disk encryption, inactivity timeouts, privacy screens, strong authentication, Bluetooth disability and removable media control and encryption (e.g. USB drives).
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- Disable (or constrict) use of removable media
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- Implement a process to remotely disable access to a device that has been lost or stolen.
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- permit the installation of apps from official sources only
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- Turn on local firewalls
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- develop effective use policies for use of public Wi-Fi networks
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**Identity and Access Management**
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- Manage account permissions, especially for administrative rights on endpoints ([A 5.15](../Standards/ISO27x/OST/27002/EN/a-5.15-Access-control.md), [A 5.18](../Standards/ISO27x/OST/27002/EN/a-5.18-Access-rights.md)). This includes:
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- Restricting write permissions for servers
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- Restricting admin users and privileged accounts
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- Granting users the lowest-level system permissions that still allow them to do their job
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- Removing abilities for users to install and run unapproved software applications / use Application whitelisting
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- Limiting administrative tools on workstations
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- creating separate user accounts for privileged and non-privileged activities
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- Organise access rights based on the principles of least privilege, need to know principle and segregation of duties
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- ensure the use of unique passwords, esp. for accounts with elevated rights
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- Use enhanced passwords and change them on a regular basis
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- Use multi-factor authentication (MFA)
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- Train your staff
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- Consider cyber liability insurance
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## Business Continuity Planning (BCP)
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[A 5.29](../Standards/ISO27x/OST/27002/EN/a-5.29-Information-security-during-disruption.md), [A 5.30](../Standards/ISO27x/OST/27002/EN/a-5.30-ICT-readiness-for-business-continuity.md)
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- Employ a comprehensive data backup and recovery plan for all high-value data
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- Backups should be isolated on external storage devices or in the cloud, disconnected and inaccessible from any potentially infected computer once the backup is completed.
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See also [BCP_Bedrijfscontinuïteitsplanning](../📚️%20Literature%20notes/BCP_Bedrijfscontinuïteitsplanning.md)
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## Ransom payment policy
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if your files are encrypted, what do you do?
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# During the attack
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Remove infected systems from the environment, by disabling physical network ports or removing the network cable.
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Check the Europol [No More Ransom project ](https://www.nomoreransom.org), specifically to see if a decryption solution is available with the [Crypto Sheriff ](https://www.nomoreransom.org/crypto-sheriff.php?lang=en)tool or on their [Decryption Tools](https://www.nomoreransom.org/en/decryption-tools.html) page.
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## Infected… What to do next?
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1. Immediately disconnect, but don’t switch off the infected device(s) from all network connections, whether wired, wireless or mobile phone based.
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2. In very serious cases, consider whether turning off your Wi-Fi, disabling any core network connections (including switches), and disconnecting from the internet might be necessary.
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3. Reset credentials, including passwords (especially for administrator and other system accounts), but verify that you are not locking yourself out of systems that are needed for recovery.
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4. [Report the incident](https://www.nomoreransom.org/en/report-a-crime.html) to your national police or other competent authority.
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5. Preserve any evidence, in coordination with the competent authorities investigating the attack: create a forensic image of affected systems (or a system snapshot), create a RAM dump of the affected systems, and preserve any netflow or other network traffic logs.
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6. Visit [www.nomoreransom.org](https://www.nomoreransom.org/) to check whether your business was infected with one of the ransomware variants for which we have [decryption tools](https://www.nomoreransom.org/en/decryption-tools.html) available free of charge. If that’s not the case, proceed with the recovery steps.
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7. Safely wipe the infected devices and reinstall the OS.
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8. Before you restore from a backup, verify that it is free from any malware. You should only restore if you are very confident that the backup and the device you are connecting it to are clean.
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9. Connect devices to a clean network to download, install and update the OS and all other software.
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10. Install, update, and run antivirus software.
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11. Reconnect to your network.
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12. Monitor network traffic and run antivirus scans to identify if any infection remains.
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# After the attack
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Inspect your environment to:
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- confirm the attackers no longer have a presence in your system
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- know if they have stolen data or caused other harm
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Harden your systems against a similar attack
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rebuild or recover systems impacted by the attack.
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- rebuild systems from known-good baseline images to counter undetected threats.
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- scan systems with an up-to-date anti-malware solution to remove malware and related artifacts.
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- block malicious domain(s) and IP addresses. This should be performed at all appropriate network filtering and domain name server devices such as firewalls, web proxies, switches, and DNS servers.
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- terminate malicious processes on the compromised endpoint(s) identified.
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- quarantine affected endpoints from the network.
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- lock affected compromised account(s) until the credentials can be rotated.
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- changing affected account(s) password(s) as soon as possible to prevent an attacker from leveraging the credentials to access services.
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- determining whether other users received malicious communications and removing them from all mailboxes.
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- blocking the sender’s email address (if applicable).
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