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Alert (AA22-074A) - Exploiting MFA and "PrintNightmare" Vulnerability

Tuesday, March 15, 2022

The Federal Bureau of Investigation (FBI) and Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint Cybersecurity Advisory (CSA) to warn organizations that Russian state-sponsored cyber actors have gained network access through exploitation of default MFA protocols and a known vulnerability. As early as May 2021, Russian state-sponsored cyber actors took advantage of a misconfigured account set to default MFA protocols at a non-governmental organization (NGO), allowing them to enroll a new device for MFA and access the victim network. The actors then exploited a critical Windows Print Spooler vulnerability, “PrintNightmare” (CVE-2021-34527) to run arbitrary code with system privileges. Russian state-sponsored cyber actors successfully exploited the vulnerability while targeting an NGO using Cisco’s Duo MFA, enabling access to cloud and email accounts for document exfiltration.

This advisory provides observed tactics, techniques, and procedures, indicators of compromise (IOCs), and recommendations to protect against Russian state-sponsored malicious cyber activity. FBI and CISA urge all organizations to apply the recommendations in the Mitigations section of this advisory, including the following:

  • Enforce MFA and review configuration policies to protect against “fail open” and re-enrollment scenarios.
  • Ensure inactive accounts are disabled uniformly across the Active Directory and MFA systems. 
  • Patch all systems. Prioritize patching for known exploited vulnerabilities.

For more general information on Russian state-sponsored malicious cyber activity, see CISA's Russia Cyber Threat Overview and Advisories webpage. For more information on the threat of Russian state-sponsored malicious cyber actors to U.S. critical infrastructure as well as additional mitigation recommendations, see joint CSA Understanding and Mitigating Russian State-Sponsored Cyber Threats to U.S. Critical Infrastructure and CISA's Shields Up Technical Guidance webpage.

Click here for a PDF version of this report.

For a downloadable copy of IOCs, see AA22-074A.stix.

Last Modified on Jun 20, 2022
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