Multiple Critical Cisco Vulnerabilities 

THE THREAT

On February 24th, 2021, Cisco announced four critical vulnerabilities as well as multiple high and medium vulnerabilities impacting a variety of Cisco products. The critical vulnerabilities all received ratings between 9.8 – and 10 out of 10 on the Common Vulnerability Scoring System (CVSS). All of the stated vulnerabilities are exploitable by remote and unauthenticated attackers. Cisco’s ACI Multi-Site Orchestrator (MSO), Application Services Engine, and Nexus 3000 and 9000 series Switches are impacted.

Exploitation has not been identified in the wild at this time. Organizations are strongly recommended to review the recent Cisco releases and apply patches for vulnerable devices.

What we’re doing about it

• MVS will automatically add the relevant plugins for these vulnerabilities once details are made available
  • MVS customers seeking assistance with their review or scans, please contact your MVS consultant or the eSentire Security Operations Center (SOC)
• eSentire security teams continue to track this topic for additional details and detection opportunities

What you should do about it

• After performing a business impact review, apply the relevant security patches provided by Cisco
  • Workarounds as a temporary alternative to patching are only available for CVE-2021-1361

Additional information

The recent critical vulnerabilities are as follows:

CVE-2021-1388 (CVSS: 10/10) - Cisco ACI Multi-Site Orchestrator (MSO) version 3.0 vulnerability, allows a remote unauthenticated attacker to bypass device authentication. Successful exploitation would allow threat actors to receive a token with administrator privileges. The vulnerability is due to improper token validation. It is worth noting that this vulnerability is only applicable when deployed on a Cisco Application Services Engine.

CVE-2021-1393/CVE-2021-1396 (CVSS: 9.8/10) - Multiple vulnerabilities in Cisco Application Services Engine version 1.1(3d) and earlier, allows an unauthenticated, remote attacker to gain privileged access to host-level operations or learn device-specific information, create diagnostic files, and make limited configuration changes. Both vulnerabilities are due to insufficient access controls.

CVE-2021-1361 (CVSS: 9.8/10) - Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches versions 9.3(5) and 9.3(6), allows an unauthenticated, remote attacker to create, delete, or overwrite arbitrary files with root privileges on the device. The vulnerability is the result of the incorrect configuration of TCP port 9075.

All of these vulnerabilities should receive a high priority for patching before exploitation in the wild is identified.

References:

[1] https://tools.cisco.com/security/center/publicationListing.x

[2] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-3000-9000-fileaction-QtLzDRy2

[3] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-mso-authbyp-bb5GmBQv

[4] https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-case-mvuln-dYrDPC6w