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 1. Home
 2. Stop Ransomware




RANSOMWARE GUIDE



Ransomware is a form of malware designed to encrypt files on a device, rendering
any files and the systems that rely on them unusable. Malicious actors then
demand ransom in exchange for decryption. In recent years, ransomware incidents
have become increasingly prevalent among the Nation’s state, local, tribal, and
territorial (SLTT) government entities and critical infrastructure
organizations.
Ransomware incidents can severely impact business processes and leave
organizations without the data they need to operate and deliver mission-critical
services. Malicious actors have adjusted their ransomware tactics over time to
include pressuring victims for payment by threatening to release stolen data if
they refuse to pay and publicly naming and shaming victims as secondary forms of
extortion. The monetary value of ransom demands has also increased, with some
demands exceeding US $1 million. Ransomware incidents have become more
destructive and impactful in nature and scope. Malicious actors engage in
lateral movement to target critical data and propagate ransomware across entire
networks. These actors also increasingly use tactics, such as deleting system
backups, that make restoration and recovery more difficult or infeasible for
impacted organizations. The economic and reputational impacts of ransomware
incidents, throughout the initial disruption and, at times, extended recovery,
have also proven challenging for organizations large and small.

On September 30, 2020, a joint Ransomware Guide was released, which is a
customer centered, one-stop resource with best practices and ways to prevent,
protect and/or respond to a ransomware attack. CISA and MS-ISAC are distributing
this guide to inform and enhance network defense and reduce exposure to a
ransomware attack:

This Ransomware Guide includes two resources:

 * Part 1: Ransomware Prevention Best Practices
 * Part 2: Ransomware Response Checklist

CISA recommends that organizations take the following initial steps:

 * Join an information sharing organization, such as one of the following:
   * Multi-State Information Sharing and Analysis Center (MS-ISAC):
     https://learn.cisecurity.org/ms-isac-registration
   * Election Infrastructure Information Sharing and Analysis Center (EI-ISAC):
     https://learn.cisecurity.org/ei-isac-registration
   * Sector-based ISACs - National Council of ISACs:
     https://www.nationalisacs.org/member-isacs
   * Information Sharing and Analysis Organization (ISAO) Standards
     Organization: https://www.isao.org/information-sharing-groups/
 * Engage CISA to build a lasting partnership and collaborate on information
   sharing, best practices, assessments, exercises, and more.
 * SLTT organizations: CyberLiaison_SLTT@cisa.dhs.gov
 * Private sector organizations: CyberLiaison_Industry@cisa.dhs.gov
 * Engaging with your ISAC, ISAO, and with CISA will enable your organization to
   receive critical information and access to services to better manage the risk
   posed by ransomware and other cyber threats.
   
    
   
   Ransomware Guide (Sept. 2020)


PART 1: RANSOMWARE PREVENTION BEST PRACTICES


BE PREPARED

Refer to the best practices and references below to help manage the risk posed
by ransomware and support your organization’s coordinated and efficient response
to a ransomware incident. Apply these practices to the greatest extent possible
based on availability of organizational resources.

 * It is critical to maintain offline, encrypted backups of data and to
   regularly test your backups. Backup procedures should be conducted on a
   regular basis. It is important that backups be maintained offline as many
   ransomware variants attempt to find and delete any accessible backups.
   Maintaining offline, current backups is most critical because there is no
   need to pay a ransom for data that is readily accessible to your
   organization.
   * Maintain regularly updated “gold images” of critical systems in the event
     they need to be rebuilt. This entails maintaining image “templates” that
     include a preconfigured operating system (OS) and associated software
     applications that can be quickly deployed to rebuild a system, such as a
     virtual machine or server.
   * Retain backup hardware to rebuild systems in the event rebuilding the
     primary system is not preferred.
     * Hardware that is newer or older than the primary system can present
       installation or compatibility hurdles when rebuilding from images.
   * In addition to system images, applicable source code or executables should
     be available (stored with backups, escrowed, license agreement to obtain,
     etc.). It is more efficient to rebuild from system images, but some images
     will not install on different hardware or platforms correctly; having
     separate access to needed software will help in these cases.
 * Create, maintain, and exercise a basic cyber incident response plan and
   associated communications plan that includes response and notification
   procedures for a ransomware incident.
   * Review available incident response guidance, such as the Public Power Cyber
     Incident Response Playbook (https://www.publicpower.
     org/system/files/documents/Public-Power-Cyber-Incident-Response-Playbook.pdf(link
     is external)), a resource and guide to:
     * Help your organization better organize around cyber incident response,
       and
     * Develop a cyber incident response plan.
   * The Ransomware Response Checklist, which forms the other half of this
     Ransomware Guide, serves as an adaptable, ransomware-specific annex to
     organizational cyber incident response or disruption plans.


RANSOMWARE INFECTION VECTOR: INTERNET-FACING VULNERABILITIES AND
MISCONFIGURATIONS

 * Conduct regular vulnerability scanning to identify and address
   vulnerabilities, especially those on internet-facing devices, to limit the
   attack surface.
   * CISA offers a no-cost Vulnerability Scanning service and other no-cost
     assessments: https://www.cisa.gov/cyber-resource-hub.
 * Regularly patch and update software and OSs to the latest available versions.
   * Prioritize timely patching of internet-facing servers—as well as software
     processing internet data, such as web browsers, browser plugins, and
     document readers—for known vulnerabilities.
 * Ensure devices are properly configured and that security features are
   enabled. For example, disable ports and protocols that are not being used for
   a business purpose (e.g., Remote Desktop Protocol [RDP] – Transmission
   Control Protocol [TCP] Port 3389).
 * Employ best practices for use of RDP and other remote desktop services.
   Threat actors often gain initial access to a network through exposed and
   poorly secured remote services, and later propagate ransomware. See CISA
   Alert AA20-073A, Enterprise VPN Security
   (https://us-cert.cisa.gov/ncas/alerts/aa20-073a).
   * Audit the network for systems using RDP, close unused RDP ports, enforce
     account lockouts after a specified number of attempts, apply multi-factor
     authentication (MFA), and log RDP login attempts.
 * Disable or block Server Message Block (SMB) protocol outbound and remove or
   disable outdated versions of SMB. Threat actors use SMB to propagate malware
   across organizations. Based on this specific threat, organizations should
   consider the following actions to protect their networks:
   * Disable SMBv1 and v2 on your internal network after working to mitigate any
     existing dependencies (on the part of existing systems or applications)
     that may break when disabled.
     * Remove dependencies through upgrades and reconfiguration: Upgrade to
       SMBv3 (or most current version) along with SMB signing.
   * Block all versions of SMB from being accessible externally to your network
     by blocking TCP port 445 with related protocols on User Datagram Protocol
     ports 137–138 and TCP port 139.


RANSOMWARE INFECTION VECTOR: PHISHING

 * Implement a cybersecurity user awareness and training program that includes
   guidance on how to identify and report suspicious activity (e.g., phishing)
   or incidents. Conduct organization-wide phishing tests to gauge user
   awareness and reinforce the importance of identifying potentially malicious
   emails.
 * Implement filters at the email gateway to filter out emails with known
   malicious indicators, such as known malicious subject lines, and block
   suspicious Internet Protocol (IP) addresses at the firewall.
 * To lower the chance of spoofed or modified emails from valid domains,
   implement Domain-based Message Authentication, Reporting and Conformance
   (DMARC) policy and verification. DMARC builds on the widely deployed sender
   policy framework and Domain Keys Identified Mail protocols, adding a
   reporting function that allows senders and receivers to improve and monitor
   protection of the domain from fraudulent email.
 * Consider disabling macro scripts for Microsoft Office files transmitted via
   email. These macros can be used to deliver ransomware.


RANSOMWARE INFECTION VECTOR: PRECURSOR MALWARE INFECTION

 * Ensure antivirus and anti-malware software and signatures are up to date.
   Additionally, turn on automatic updates for both solutions. CISA recommends
   using a centrally managed antivirus solution. This enables detection of both
   “precursor” malware and ransomware.
   * A ransomware infection may be evidence of a previous, unresolved network
     compromise. For example, many ransomware infections are the result of
     existing malware infections, such as TrickBot, Dridex, or Emotet.
   * In some cases, ransomware deployment is just the last step in a network
     compromise and is dropped as a way to obfuscate previous post-compromise
     activities.
 * Use application directory allowlisting on all assets to ensure that only
   authorized software can run, and all unauthorized software is blocked from
   executing.
   * Enable application directory allowlisting through Microsoft Software
     Restriction Policy or AppLocker.
   * Use directory allowlisting rather than attempting to list every possible
     permutation of applications in a network environment. Safe defaults allow
     applications to run from PROGRAMFILES, PROGRAMFILES(X86), and SYSTEM32.
     Disallow all other locations unless an exception is granted.
 * Consider implementing an intrusion detection system (IDS) to detect command
   and control activity and other potentially malicious network activity that
   occurs prior to ransomware deployment.


RANSOMWARE INFECTION VECTOR: THIRD PARTIES AND MANAGED SERVICE PROVIDERS

 * Take into consideration the risk management and cyber hygiene practices of
   third parties or managed service providers (MSPs) your organization relies on
   to meet its mission. MSPs have been an infection vector for ransomware
   impacting client organizations.
   * If a third party or MSP is responsible for maintaining and securing your
     organization’s backups, ensure they are following the applicable best
     practices outlined above. Using contract language to formalize your
     security requirements is a best practice.
 * Understand that adversaries may exploit the trusted relationships your
   organization has with third parties and MSPs. See CISA’s APTs Targeting IT
   Service Provider Customers (https://
   us-cert.cisa.gov/APTs-Targeting-IT-Service-Provider-Customers).
   * Adversaries may target MSPs with the goal of compromising MSP client
     organizations; they may use MSP network connections and access to client
     organizations as a key vector to propagate malware and ransomware.
   * Adversaries may spoof the identity of—or use compromised email accounts
     associated with—entities your organization has a trusted relationship with
     in order to phish your users, enabling network compromise and disclosure of
     information.


GENERAL BEST PRACTICES AND HARDENING GUIDANCE

 * Employ MFA for all services to the extent possible, particularly for webmail,
   virtual private networks, and accounts that access critical systems.
   * If you are using passwords, use strong passwords
     (https://us-cert.cisa.gov/ncas/tips/ST04-002) and do not reuse passwords
     for multiple accounts. Change default passwords. Enforce account lockouts
     after a specified number of login attempts. Password managers can help you
     develop and manage secure passwords.
 * Apply the principle of least privilege to all systems and services so that
   users only have the access they need to perform their jobs. Threat actors
   often seek out privileged accounts to leverage to help saturate networks with
   ransomware.
   * Restrict user permissions to install and run software applications.
   * Limit the ability of a local administrator account to log in from a local
     interactive session (e.g., “Deny access to this computer from the
     network.”) and prevent access via an RDP session.
   * Remove unnecessary accounts and groups and restrict root access.
   * Control and limit local administration.
   * Make use of the Protected Users Active Directory group in Windows domains
     to further secure privileged user accounts against pass-the-hash attacks.
   * Audit user accounts regularly, particularly Remote Monitoring and
     Management accounts that are publicly accessible—this includes audits of
     third-party access given to MSPs.
 * Leverage best practices and enable security settings in association with
   cloud environments, such as Microsoft Office 365
   (https://www.us-cert.cisa.gov/ncas/alerts/aa20-120a).
 * Develop and regularly update a comprehensive network diagram that describes
   systems and data flows within your organization’s network (see figure 1).
   This is useful in steady state and can help incident responders understand
   where to focus their efforts.
   * The diagram should include depictions of covered major networks, any
     specific IP addressing schemes, and the general network topology (including
     network connections, interdependencies, and access granted to third parties
     or MSPs).
 * Employ logical or physical means of network segmentation to separate various
   business unit or departmental IT resources within your organization as well
   as to maintain separation between IT and operational technology. This will
   help contain the impact of any intrusion affecting your organization and
   prevent or limit lateral movement on the part of malicious actors. See
   figures 2 and 3 for depictions of a flat (unsegmented) network and of a best
   practice segmented network.
   * Network segmentation can be rendered ineffective if it is breached through
     user error or non-adherence to organizational policies (e.g., connecting
     removable storage media or other devices to multiple segments).



 * Ensure your organization has a comprehensive asset management approach.
   * Understand and inventory your organization’s IT assets, both logical (e.g.,
     data, software) and physical (e.g., hardware).
   * Understand which data or systems are most critical for health and safety,
     revenue generation, or other critical services, as well as any associated
     interdependencies (i.e., “critical asset or system list”). This will aid
     your organization in determining restoration priorities should an incident
     occur. Apply more comprehensive security controls or safeguards to critical
     assets. This requires organization-wide coordination.
   * Use the MS-ISAC Hardware and Software Asset Tracking Spreadsheet:
     https://www.cisecurity.
     org/white-papers/cis-hardware-and-software-asset-tracking-spreadsheet/.
 * Restrict usage of PowerShell, using Group Policy, to specific users on a
   case-by-case basis. Typically, only those users or administrators who manage
   the network or Windows OSs should be permitted to use PowerShell. Update
   PowerShell and enable enhanced logging. PowerShell is a cross-platform,
   command-line, shell and scripting language that is a component of Microsoft
   Windows. Threat actors use PowerShell to deploy ransomware and hide their
   malicious activities.
   * Update PowerShell instances to version 5.0 or later and uninstall all
     earlier PowerShell versions. Logs from PowerShell prior to version 5.0 are
     either non-existent or do not record enough detail to aid in enterprise
     monitoring and incident response activities.
     * PowerShell logs contain valuable data, including historical OS and
       registry interaction and possible tactics, techniques, and procedures of
       a threat actor’s PowerShell use.
   * Ensure PowerShell instances (use most current version) have module, script
     block, and transcription logging enabled (enhanced logging).
     * The two logs that record PowerShell activity are the “PowerShell” Windows
       Event Log and the “PowerShell Operational” Log. CISA recommends turning
       on these two Windows Event Logs with a retention period of 180 days.
       These logs should be checked on a regular basis to confirm whether the
       log data has been deleted or logging has been turned off. Set the storage
       size permitted for both logs to as large as possible.



 * Secure domain controllers (DCs). Threat actors often target and use DCs as a
   staging point to spread ransomware network-wide.
   * The following list contains high-level suggestions on how best to secure a
     DC:
     * Ensure that DCs are regularly patched. This includes the application of
       critical patches as soon as possible.
     * Ensure the most current version of the Windows Server OS is being used on
       DCs. Security features are better integrated in newer versions of Windows
       Server OSs, including Active Directory security features. Use Active
       Directory configuration guides, such as those available from Microsoft
       (https://docs.microsoft.com/
       en-us/windows-server/identity/ad-ds/plan/security-best-practices/best-practices-forsecuring-active-directory),
       when configuring available security features.
     * Ensure that no additional software or agents are installed on DCs, as
       these can be leveraged to run arbitrary code on the system.
     * Access to DCs should be restricted to the Administrators group. Users
       within this group should be limited and have separate accounts used for
       day-to-day operations with non-administrative permissions.
     * DC host firewalls should be configured to prevent internet access.
       Usually, these systems do not have a valid need for direct internet
       access. Update servers with internet connectivity can be used to pull
       necessary updates in lieu of allowing internet access for DCs.
   * CISA recommends the following DC Group Policy settings:
     (Note: This is not an all-inclusive list and further steps should be taken
     to secure DCs within the environment.)
     * The Kerberos default protocol is recommended for authentication, but if
       it is not used, enable NTLM auditing to ensure that only NTLMv2 responses
       are being sent across the network. Measures should be taken to ensure
       that LM and NTLM responses are refused, if possible.
     * Enable additional protections for Local Security Authentication to
       prevent code injection capable of acquiring credentials from the system.
       Prior to enabling these protections, run audits against the lsass.exe
       program to ensure an understanding of the programs that will be affected
       by the enabling of this protection.
     * Ensure that SMB signing is required between the hosts and the DCs to
       prevent the use of replay attacks on the network. SMB signing should be
       enforced throughout the entire domain as an added protection against
       these attacks elsewhere in the environment.
   * Retain and adequately secure logs from both network devices and local
     hosts. This supports triage and remediation of cybersecurity events. Logs
     can be analyzed to determine the impact of events and ascertain whether an
     incident has occurred.
     9
     * Set up centralized log management using a security information and event
       management tool. This enables an organization to correlate logs from both
       network and host security devices. By reviewing logs from multiple
       sources, an organization can better triage an individual event and
       determine its impact to the organization as a whole.
     * Maintain and back up logs for critical systems for a minimum of one year,
       if possible.
 * Baseline and analyze network activity over a period of months to determine
   behavioral patterns
   so that normal, legitimate activity can be more easily distinguished from
   anomalous network
   activity (e.g., normal vs anomalous account activity).
   * Business transaction logging—such as logging activity related to specific
     or critical
     applications—is another useful source of information for behavioral
     analytics.


CONTACT CISA FOR THESE NO-COST RESOURCES

 * Information sharing with CISA and MS-ISAC (for SLTT organizations) includes
   bi-directional sharing of best practices and network defense information
   regarding ransomware trends and variants as well as malware that is a
   precursor to ransomware
 * Policy-oriented or technical assessments help organizations understand how
   they can improve their defenses to avoid ransomware infection:
   https://www.cisa.gov/cyber-resource-hub
   * Assessments include Vulnerability Scanning and Phishing Campaign Assessment
 * Cyber exercises evaluate or help develop a cyber incident response plan in
   the context of a ransomware incident scenario
 * CISA Cybersecurity Advisors (CSAs) advise on best practices and connect you
   with CISA resources to manage cyber risk
 * Contacts:
   * SLTT organizations: CyberLiaison_SLTT@cisa.dhs.gov
   * Private sector organizations: CyberLiaison_Industry@cisa.dhs.gov


RANSOMWARE QUICK REFERENCES

 * Security Primer – Ransomware (MS-ISAC): Outlines opportunistic and strategic
   ransomware campaigns, common infection vectors, and best practice
   recommendations:
   https://www.cisecurity.org/white-papers/security-primer-ransomware/(link is
   external)
 * Ransomware: Facts, Threats, and Countermeasures (MSISAC):
   Facts about ransomware, infection vectors, ransomware
   capabilities, and how to mitigate the risk of ransomware
   infection: https://www.cisecurity.org/blog/ransomwarefacts-
   threats-and-countermeasures/(link is external)
 * Security Primer – Ryuk (MS-ISAC): Overview of Ryuk ransomware, a prevalent
   ransomware variant in the SLTT government sector, that includes information
   regarding preparedness steps organizations can take to guard against
   infection: https://www.cisecurity.org/white-papers/security-primer-ryuk/(link
   is external)


PART 2: RANSOMWARE RESPONSE CHECKLIST

Should your organization be a victim of ransomware, CISA strongly recommends
responding by using the following checklist. Be sure to move through the first
three steps in sequence.


DETECTION AND ANALYSIS

 1.  Determine which systems were impacted, and immediately isolate them.
     1. If several systems or subnets appear impacted, take the network offline
        at the switch level. It may not be feasible to disconnect individual
        systems during an incident.
     2. If taking the network temporarily offline is not immediately possible,
        locate the network (e.g., Ethernet) cable and unplug affected devices
        from the network or remove them from Wi-Fi to contain the infection.
     3. After an initial compromise, malicious actors may monitor your
        organization’s activity or communications to understand if their actions
        have been detected. Be sure to isolate systems in a coordinated manner
        and use out-of-band communication methods like phone calls or other
        means to avoid tipping off actors that they have been discovered and
        that mitigation actions are being undertaken. Not doing so could cause
        actors to move laterally to preserve their access—already a common
        tactic—or deploy ransomware widely prior to networks being taken
        offline.
     4. Note: Step 2 will prevent you from maintaining ransomware infection
        artifacts and potential evidence stored in volatile memory. It should be
        carried out only if it is not possible to temporarily shut down the
        network or disconnect affected hosts from the network using other means.
 2.  Only in the event you are unable to disconnect devices from the network,
     power them down to avoid further spread of the ransomware infection.
 3.  Triage impacted systems for restoration and recovery.
     1. Identify and prioritize critical systems for restoration, and confirm
        the nature of data housed on impacted systems.
        1. Prioritize restoration and recovery based on a predefined critical
           asset list that includes information systems critical for health and
           safety, revenue generation, or other critical services, as well as
           systems they depend on.
        2. Keep track of systems and devices that are not perceived to be
           impacted so they can be deprioritized for restoration and recovery.
           This enables your organization to get back to business in a more
           efficient manner.
 4.  Confer with your team to develop and document an initial understanding of
     what has occurred based on initial analysis.
 5.  Using the contact information below, engage your internal and external
     teams and stakeholders with an understanding of what they can provide to
     help you mitigate, respond to, and recover from the incident.
     1. Share the information you have at your disposal to receive the most
        timely and relevant assistance. Keep management and senior leaders
        informed via regular updates as the situation develops. Relevant
        stakeholders may include your IT department, managed security service
        providers, cyber insurance company, and departmental or elected leaders.
 6.  Take a system image and memory capture of a sample of affected devices
     (e.g., workstations and servers). Additionally, collect any relevant logs
     as well as samples of any “precursor” malware binaries and associated
     observables or indicators of compromise (e.g., suspected command and
     control IP addresses, suspicious registry entries, or other relevant files
     detected). The contacts below may be able to assist you in performing these
     tasks.
     1. Take care to preserve evidence that is highly volatile in nature—or
        limited in retention—to prevent loss or tampering (e.g., system memory,
        Windows Security logs, data in firewall log buffers).
 7.  Consult federal law enforcement regarding possible decryptors available, as
     security researchers have already broken the encryption algorithms for some
     ransomware variants.
 8.  Research the trusted guidance (i.e., published by sources such as
     government, MS-ISAC, reputable security vendor, etc.) for the particular
     ransomware variant and follow any additional recommended steps to identify
     and contain systems or networks that are confirmed to be impacted.
     1. Kill or disable the execution of known ransomware binaries; this will
        minimize damage and impact to your systems. Delete other known,
        associated registry values and files.
 9.  Identify the systems and accounts involved in the initial breach. This can
     include email accounts.
 10. Based on the breach or compromise details determined above, contain any
     associated systems that may be used for further or continued unauthorized
     access. Breaches often involve mass credential exfiltration. Securing the
     network and other information sources from continued credential-based
     unauthorized access may include the following actions:
     1. Disabling virtual private networks, remote access servers, single
        sign-on resources, and cloud-based or other public-facing assets.
 11. Additional suggested actions—server-side data encryption
     quick-identification steps:
     1. In the event you learn that server-side data is being encrypted by an
        infected workstation, quick-identification steps are to:
        1. Review Computer Management > Sessions and Open Files lists on
           associated servers to determine the user or system accessing those
           files.
        2. Review file properties of encrypted files or ransom notes to identify
           specific users that may be associated with file ownership.
        3. Review the TerminalServices-RemoteConnectionManager event log to
           check for successful RDP network connections.
        4. Review the Windows Security log, SMB event logs, and
           any related logs that may identify significant authentication
           or access events.
        5. Run Wireshark on the impacted server with a filter to
           identify IP addresses involved in actively writing or renaming
           files (e.g., "smb2.filename contains cryptxxx").
 12. Conduct an examination of existing organizational detection or prevention
     systems (antivirus, Endpoint Detection & Response, IDS, Intrusion
     Prevention System, etc.) and logs. Doing so can highlight evidence of
     additional systems or malware involved in earlier stages of the attack.
     1. Look for evidence of precursor “dropper” malware. A ransomware event may
        be evidence of a previous, unresolved network compromise. Many
        ransomware infections are the result of existing malware infections such
        as TrickBot, Dridex, or Emotet.
        1. Operators of these advanced malware variants will often sell access
           to a network. Malicious actors will sometimes use this access to
           exfiltrate data and then threaten to release the data publicly before
           ransoming the network in an attempt to further extort the victim and
           pressure them into paying.
        2. Malicious actors often drop manually deployed ransomware variants on
           a network to obfuscate their post-compromise activity. Care must be
           taken to identify such dropper malware before rebuilding from backups
           to prevent continuing compromise.
 13. Conduct extended analysis to identify outside-in and inside-out persistence
     mechanisms.
     1. Outside-in persistence may include authenticated access to external
        systems via rogue accounts, backdoors on perimeter systems, exploitation
        of external vulnerabilities, etc.
     2. Inside-out persistence may include malware implants on the internal
        network or a variety of living-off-the-land style modifications (e.g.,
        use of commercial penetration testing tools like Cobalt Strike; use of
        PsTools suite, including PsExec, to remotely install and control malware
        and gather information regarding—or perform remote management of—Windows
        systems; use of PowerShell scripts).
     3. Identification may involve deployment of endpoint detection and response
        solutions, audits of local and domain accounts, examination of data
        found in centralized logging systems, or deeper forensic analysis of
        specific systems once movement within the environment has been mapped
        out.
 14. Rebuild systems based on a prioritization of critical services (e.g.,
     health and safety or revenue generating services), using pre-configured
     standard images, if possible.
 15. Once the environment has been fully cleaned and rebuilt (including any
     associated impacted accounts and the removal or remediation of malicious
     persistence mechanisms) issue password resets for all affected systems and
     address any associated vulnerabilities and gaps in security or visibility.
     This can include applying patches, upgrading software, and taking other
     security precautions not previously taken.
 16. Based on established criteria, which may include taking the steps above or
     seeking outside assistance, the designated IT or IT security authority
     declares the ransomware incident over.
 17. Reconnect systems and restore data from offline, encrypted backups based on
     a prioritization of critical services.
     1. Take care not to re-infect clean systems during recovery. For example,
        if a new Virtual Local Area Network has been created for recovery
        purposes, ensure only clean systems are added to it.
 18. Document lessons learned from the incident and associated response
     activities to inform updates to—and refine—organizational policies, plans,
     and procedures and guide future exercises of the same.
 19. Consider sharing lessons learned and relevant indicators of compromise with
     CISA or your sector ISAC/ISAO for further sharing and to benefit others
     within the community.


FEDERAL ASSET RESPONSE CONTACTS

Upon voluntary request, federal asset response includes providing technical
assistance to affected entities to protect their assets, mitigate
vulnerabilities, and reduce impacts of cyber incidents while identifying other
entities that may be at risk, assessing potential risks to the sector or region,
facilitating information sharing and operational coordination, and providing
guidance on how to best use federal resources and capabilities.
What You Can Expect:

 * Specific guidance to help evaluate and remediate ransomware incidents
 * Remote assistance to identify the extent of the compromise and
   recommendations for appropriate containment and mitigation strategies
   (dependent on specific ransomware variant)
 * Phishing email, storage media, log and malware analysis, based on voluntary
   submission (full-disk forensics can be performed on an as-needed basis)
 * Contacts:
   * CISA:
     * https://us-cert.cisa.gov/report, Central@cisa.gov or (888) 282-0870
   * Cybersecurity Advisor:
     * https://www.cisa.gov/cisa-regions): [Enter your local CISA CSA’s phone
       number and email address.]
   * MS-ISAC:
     * soc@msisac.org or (866) 787-4722


FEDERAL THREAT RESPONSE CONTACTS

Upon voluntary request, federal threat response includes law enforcement and
national security investigative activity: collecting evidence and intelligence,
providing attribution, linking related incidents, identifying additional
affected entities, identifying threat pursuit and disruption opportunities,
developing and executing action to mitigate the immediate threat, and
facilitating information sharing and operational coordination with asset
response.

What You Can Expect:

 * Assistance in conducting a criminal investigation, which may involve
   collecting incident artifacts, to include system images and malware samples.
 * Contacts:
   * FBI:
     * https://www.fbi.gov/contact-us/fieldoffices
     * [Enter your local FBI field office POC phone number and email address.]
   * USSS:
     * https://www.secretservice.gov/contact/field-offices/
     * [Enter your local USSS field office POC phone number and email address.]

 

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