#VU84794 Exposed dangerous method or function in Email Security Gateway (ESG) - CVE-2023-7102

Vulnerability identifier: #VU84794

Vulnerability risk: Critical

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2023-7102

CWE-ID: CWE-749

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Email Security Gateway (ESG)
Server applications / DLP, anti-spam, sniffers

Vendor: Barracuda Networks

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.

Mitigation
On December 22, 2023, Barracuda deployed a patch to remediate compromised ESG appliances which exhibited indicators of compromise related to the newly identified malware variants.

Vulnerable software versions

Email Security Gateway (ESG): 5.1.3 - 9.2.1.001

---

External links
https://www.barracuda.com/company/legal/esg-vulnerability
https://www.cve.org/CVERecord?id=CVE-2023-7101
https://metacpan.org/dist/Spreadsheet-ParseExcel
https://github.com/haile01/perl_spreadsheet_excel_rce_poc
https://github.com/jmcnamara/spreadsheet-parseexcel/blob/c7298592e102a375d43150cd002feed806557c15/lib/Spreadsheet/ParseExcel/Utility.pm#L171
https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2023/MNDT-2023-0019.md

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.