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Rewterz Threat Advisory – Multiple Vulnerabilities in OpenSSL Affecting Cisco Products

Severity

High

Analysis Summary

CVE-2021-3449

OpenSSL is vulnerable to a denial of service, caused by a NULL pointer dereference in signature_algorithms processing. By sending a specially crafted renegotiation ClientHello message from a client, a remote attacker could exploit this vulnerability to cause the TLS server to crash.

CVE-2021-3450

OpenSSL could allow a remote attacker to bypass security restrictions, caused by a missing check in the validation logic of X.509 certificate chains by the X509_V_FLAG_X509_STRICT flag. By using any valid certificate or certificate chain to sign a specially crafted certificate, an attacker could bypass the check that non-CA certificates must not be able to issue other certificates and override the default purpose.

The exploitation of these vulnerabilities could allow an attacker to use a valid non-certificate authority (CA) certificate to act as a CA and sign a certificate for an arbitrary organization, user or device, or to cause a denial of service (DoS) condition.

Impact

  • Denial of Service
  • Bypass Security

Affected Vendors

Cisco

Affected Products

  • Cisco Webex Meetings Server
  • Cisco Meraki MS390
  • Cisco Firepower 9300 Security Appliances
  • Cisco Firepower 4100 Series Appliance
  • Cisco Nexus 3000 Series Switches (NX-OS 10.1)
  • Cisco Small Business RV Series RV320 Dual Gigabit WAN VPN Route
  • Cisco UCS Standalone C-Series Rack Server – Integrated Management Controller
  • Cisco Security Manager

Remediation

Refer to Cisco Security Advisory for the patch, upgrade, or suggested workaround information.

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-openssl-2021-GHY28dJd