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CVE-2023-2868: Barracuda Networks ESG Appliance Improper Input Validation Vulnerability

CVE-2023-2868 is rated critical with a CVSS v3.1 base score of 9.8 and affects Barracuda Networks Email Security Gateway (ESG) Appliance, along with 5 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-05-26, which means exploitation in the wild has been observed.

Vulnerability description

A remote command injection vulnerability exists in the Barracuda Email Security Gateway (appliance form factor only) product effecting versions 5.1.3.001-9.2.0.006. The vulnerability arises out of a failure to comprehensively sanitize the processing of .tar file (tape archives). The vulnerability stems from incomplete input validation of a user-supplied .tar file as it pertains to the names of the files contained within the archive. As a consequence, a remote attacker can specifically format these file names in a particular manner that will result in remotely executing a system command through Perl's qx operator with the privileges of the Email Security Gateway product. This issue was fixed as part of BNSF-36456 patch. This patch was automatically applied to all customer appliances.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-20: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CWE-77: Improper Neutralization of Special Elements used in a Command

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected products

  • Barracuda Email Security Gateway 300 Firmware: from 5.1.3.001 up to and including 9.2.0.006
  • Barracuda Email Security Gateway 400 Firmware: from 5.1.3.001 up to and including 9.2.0.006
  • Barracuda Email Security Gateway 600 Firmware: from 5.1.3.001 up to and including 9.2.0.006
  • Barracuda Email Security Gateway 800 Firmware: from 5.1.3.001 up to and including 9.2.0.006
  • Barracuda Email Security Gateway 900 Firmware: from 5.1.3.001 up to and including 9.2.0.006

References