Cyber Resilience

CVE-2023-2868

RCE in Barracuda Email Security Gateway 300 Firmware 5.1.3.001 – 9.2.0.006

CISA KEVActive ExploitationEUVD ExploitedRCECommand Injection
Published
24 May 2023
Modified
24 October 2025
KEV Added
26 May 2023
Patch / advisory
CVSS Score v3.1 9.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS Score 0.87 99.7th percentile
Risk Priority 95 floored blend · peak EPSS

Summary

CVE-2023-2868 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Barracuda Email Security Gateway 300 Firmware. Its CVSS base score is 9.4 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A remote command injection vulnerability affects the Barracuda Email Security Gateway appliance in versions 5.1.3.001 through 9.2.0.006. The flaw stems from incomplete input validation when processing .tar archives, specifically the names of files contained within them. An attacker can craft archive entries that cause Perl's qx operator to execute arbitrary system commands with the privileges of the Email Security Gateway product. The issue is tracked under CWE-20 and CWE-77 and carries a CVSS 3.1 score of 9.4.

An unauthenticated remote attacker can exploit the vulnerability by sending a specially formatted .tar file to the appliance. Successful exploitation grants the ability to run commands on the underlying system, potentially leading to full compromise of the email security gateway with impacts on confidentiality, integrity, and limited availability.

Barracuda addressed the issue via patch BNSF-36456, which was automatically deployed to all customer appliances. Public advisories from Barracuda and CISA confirm the fix and note that the vulnerability has been observed in active exploitation campaigns.

The CVE appears in CISA's Known Exploited Vulnerabilities catalog. Its EPSS score reached a peak of 0.9145 and currently stands at 0.8921, indicating sustained exploitation interest after disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
KEV Date Added
26 May 2023

Related Threats

Threat-Actor AttributionAI

UNC4841
Mandiant publicly attributed mass exploitation of this Barracuda ESG zero-day to UNC4841 espionage operations (2023 reporting).

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.008 Network Device CLI Execution
Adversaries may abuse scripting or built-in command line interpreters (CLI) on network devices to execute malicious command and payloads.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-3400Shared CWE-20, CWE-77both on KEV
CVE-2018-19949Shared CWE-20, CWE-77both on KEV
CVE-2023-1389Shared CWE-77both on KEV
CVE-2012-1823Shared CWE-77both on KEV
CVE-2019-0541Shared CWE-77both on KEV
CVE-2005-2773Shared CWE-77both on KEV
CVE-2020-25079Shared CWE-77both on KEV
CVE-2022-40765Shared CWE-77both on KEV
CVE-2023-20118Shared CWE-77both on KEV
CVE-2024-3273Shared CWE-77both on KEV

Affected Assets

barracuda
email security gateway 300 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 400 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 600 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 800 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 900 firmware
5.1.3.001 — 9.2.0.006

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V1.2.3
  • V1.2.5
  • V1.2.8
  • V1.2.9

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data can detect anomalous command execution resulting from injection.

ID.RA-01 partial match
prevents

Identifying recorded vulnerabilities enables remediation of command-injection flaws before exploitation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Secure coding standards require proper escaping and parameterization of commands, directly eliminating CWE-77.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

prevents

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

none

Environment separation limits the blast radius of an exploited command injection but does not prevent the flaw itself.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References