Zero-day vulnerability in Email Security Gateway (ESG)

Exposed dangerous method or function
CVE-2023-7102

It is believed that behind vulnerability exploitation is the China nexus actor tracked as UNC4841.

Known malware:

SEASPY, SALTWATER

Vulnerability details

Advisory: SB2023122712 - Remote code execution in Barracuda Email Security Gateway Appliance (ESG)

Vulnerable component: Email Security Gateway (ESG)

CVE-ID: CVE-2023-7102

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-749 - Exposed Dangerous Method or Function

Description:

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to improper input validation within the third-party Perl library Spreadsheet::ParseExcel used to parse Excel files. A remote attacker can send a specially crafted email with a malicious file inside and execute arbitrary code on the device.

Note, the vulnerability is being actively exploited in the wild.

External links:

https://www.barracuda.com/company/legal/esg-vulnerability

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.