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December 13, 2020
Mitigate SolarWinds Orion Code Compromise
This page contains a web-friendly version of the Cybersecurity and Infrastructure Security Agency’s Emergency Directive 21-01, “Mitigate SolarWinds Orion Code Compromise”.
Section 3553(h) of title 44, U.S. Code, authorizes the Secretary of Homeland Security, in response to a known or reasonably suspected information security threat, vulnerability, or incident that represents a substantial threat to the information security of an agency, to “issue an emergency directive to the head of an agency to take any lawful action with respect to the operation of the information system, including such systems used or operated by another entity on behalf of an agency, that collects, processes, stores, transmits, disseminates, or otherwise maintains agency information, for the purpose of protecting the information system from, or mitigating, an information security threat.” 44 U.S.C. § 3553(h)(1)–(2)
Section 2205(3) of the Homeland Security Act of 2002, as amended, delegates this authority to the Director of the Cybersecurity and Infrastructure Security Agency. 6 U.S.C. § 655(3).
Federal agencies are required to comply with these directives. 44 U.S.C. § 3554 (a)(1)(B)(v)
These directives do not apply to statutorily-defined “national security systems” nor to systems operated by the Department of Defense or the Intelligence Community. 44 U.S.C. § 3553(d), (e)(2), (e)(3), (h)(1)(B).
SolarWinds Orion products (affected versions are 2019.4 through 2020.2.1 HF1) are currently being exploited by malicious actors. This tactic permits an attacker to gain access to network traffic management systems. Disconnecting affected devices, as described below in Required Action 2, is the only known mitigation measure currently available.
CISA has determined that this exploitation of SolarWinds products poses an unacceptable risk to Federal Civilian Executive Branch agencies and requires emergency action. This determination is based on:
Current exploitation of affected products and their widespread use to monitor traffic on major federal network systems;
High potential for a compromise of agency information systems;
Grave impact of a successful compromise.
CISA understands that the vendor is working to provide updated software patches. However, agencies must wait until CISA provides further guidance before using any forthcoming patches to reinstall the SolarWinds Orion software in their enterprise.
Please refer to the MITRE ATT&CK framework for possible tactics the threat actors are using to maintain persistence in the environment.
This emergency directive requires the following actions:
Agencies that have the expertise to take the following actions immediately must do so before proceeding to Action 2. Agencies without this capability shall proceed to Action 2.
a. Forensically image system memory and/or host operating systems hosting all instances of SolarWinds Orion versions 2019.4 through 2020.2.1 HF1]. Analyze for new user or service accounts, privileged or otherwise.
b. Analyze stored network traffic for indications of compromise, including new external DNS domains to which a small number of agency hosts (e.g., SolarWinds systems) have had connections.
Affected agencies shall immediately disconnect or power down SolarWinds Orion products, versions 2019.4 through 2020.2.1 HF1, from their network. Until such time as CISA directs affected entities to rebuild the Windows operating system and reinstall the SolarWinds software package, agencies are prohibited from (re)joining the Windows host OS to the enterprise domain. Affected entities should expect further communications from CISA and await guidance before rebuilding from trusted sources utilizing the latest version of the product available. Additionally:
a. Block all traffic to and from hosts, external to the enterprise, where any version of SolarWinds Orion software has been installed.
b. Identify and remove all threat actor-controlled accounts and identified persistence mechanisms.
By 12pm Eastern Standard Time on Monday December 14, 2020 agencies shall report as an incident to CISA (at https://us-cert.cisa.gov/report) the existence of any of the following:
a. [SolarWinds.Orion.Core.BusinessLayer.dll] with a file hash of [b91ce2fa41029f6955bff20079468448]
c. Other indicators related to this issue to be shared by CISA
After (and only after) all threat actor-controlled accounts and identified persistence mechanisms have been removed:
a. Treat all hosts monitored by the SolarWinds Orion monitoring software as compromised by threat actors and assume that further persistence mechanisms have been deployed.
b. Rebuild hosts monitored by the SolarWinds Orion monitoring software using trusted sources.
c. Reset all credentials used by or stored in SolarWinds software. Such credentials should be considered compromised.
d. Take actions to remediate kerberoasting, including, as necessary or appropriate, engaging with a 3rd party with experience eradicating APTs from enterprise networks. For Windows environments, refer to the following:
See Microsoft’s documentation on kerberoasting: https://techcommunity.microsoft.com/t5/microsoft-security-and/detecting-ldap-based-kerberoasting-with-azure-atp/ba-p/462448
Require use of long and complex passwords (greater than 25 characters) for service principal accounts and implement a good rotation policy for these passwords.
Replace the user account by Group Managed Service Account (gMSA). See https://docs.microsoft.com/en-us/windows-server/security/group-managed-service-accounts/group-managed-service-accounts-overview and Implement Group Managed Service Accounts: https://docs.microsoft.com/en-us/windows-server/security/group-managed-service-accounts/group-managed-service-accounts-overview.
Set account options for service accounts to support AES256_CTS_HMAC_SHA1_96 and not support DES, RC4, or AES128 bit encryption
Define the Security Policy setting, for Network Security: Configure Encryption types allowed for Kerberos. Set the allowable encryption types to AES256_HMAC_SHA1 and Future encryption types. https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/network-security-configure-encryption-types-allowed-for-kerberos
See Microsoft’s documentation on how to reset the Kerberos Ticket Granting Ticket password, twice: https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-resetting-the-krbtgt-password
By 12pm Eastern Standard Time on Monday December 14, 2020, submit a report to CISA using the provided template. Department-level Chief Information Officers (CIOs) or equivalents must submit completion reports attesting to CISA that the affected devices were either disconnected or powered down.
These requirements apply to any agency network utilizing the SolarWinds Orion product. This includes any information system used or operated by another entity on behalf of an agency, that collects, processes, stores, transmits, disseminates, or otherwise maintains agency information.
CISA will continue to work with our partners to monitor for active exploitation associated with this vulnerability. CISA will release additional indicators of compromise as they become available.
CISA will provide additional guidance to agencies via the CISA website, through an emergency directive issuance coordination call, and through individual engagements upon request (via CyberDirectives@cisa.dhs.gov).
This emergency directive remains in effect until all agencies have applied the forthcoming patch or the directive is terminated through other appropriate action.
General information, assistance, and reporting – CyberDirectives@cisa.dhs.gov
Reporting indications of potential compromise – Central@cisa.dhs.gov
Frequently Asked Questions
Answers to common questions appear below.
What does the directive mean by “expertise”?
By “expertise”, we mean that you have staff or supporting personnel that are properly trained in taking a forensic image of system memory and have tooling readily-available to immediately do so.