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CVE-2023-2868 – Barracuda Zero-Day Vulnerability

May 31, 2023 | 2 MINS READ

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On May 23rd, the email security company Barracuda disclosed a new vulnerability impacting Barracuda Email Security Gateway (ESG) appliances. Exploitation of the vulnerability, by threat actors in the wild, has been confirmed, and additional technical details relating to real-world attacks were shared by Barracuda in an update on May 30th.

The vulnerability tracked as CVE-2023-2868 (CVSS: 9.4) is a remote command injection vulnerability that impacts Barracuda ESG versions A remote and unauthenticated threat actor may exploit the vulnerability to execute code on vulnerable assets, leading to deployment of malware and data theft. Exploitation of CVE-2023-2868 has been ongoing since at least October 2022.

Organizations are strongly recommended to validate patch deployment and review all potentially impacted devices for signs of compromise.

What we’re doing about it

What you should do about it

If exploitation has been confirmed /the organization has been contacted by Barracuda related to exploitation of CVE-2023-2868:

Additional information

Exploitation of CVE-2023-2868 is possible due to improper input validation of user-supplied .tar files. A remote attacker may format file names in a specific way to enable the remote execution of system commands via Perl's qx operator. Commands are executed under the same privileges as the ESG Gateway product, and no user interaction is required.

The investigation into CVE-2023-2868 and its exploitation remains ongoing at the time of writing. Barracuda has not confirmed how many organizations were impacted by attacks, but they do state that, “CVE-2023-2868 was utilized to obtain unauthorized access to a subset of ESG appliances” and “evidence of data exfiltration was identified on a subset of impacted appliances”. Barracuda has notified all organizations that were identified as being impacted by attacks exploiting CVE-2023-2868.

In real-world attacks, unidentified threat actors exploited the vulnerability for initial access into victim organizations. Once access was achieved, both novel and known customized malware were deployed to victim organizations. Observed malware includes:

While no attribution has been given at this time, based on the exploitation of a zero-day vulnerability, the use of previously unseen malware, and the avoidance of any detection for seven months, it is probable that this campaign was carried out by a sophisticated and capable threat actor group that is well resourced.


[1] https://status.barracuda.com/incidents/34kx82j5n4q9
[2] https://www.barracuda.com/company/legal/esg-vulnerability
[3] https://nvd.nist.gov/vuln/detail/CVE-2023-2868

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