CVE-2023-2868 in Email Security Gateway
Summary
by MITRE • 05/24/2023
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.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability described in CVE-2023-2868 represents a critical remote command injection flaw within the Barracuda Email Security Gateway appliance, specifically affecting versions ranging from 5.1.3.001 through 9.2.0.006. This security weakness manifests through inadequate sanitization processes during the handling of .tar file archives, creating an exploitable condition that allows remote attackers to execute arbitrary system commands with elevated privileges. The flaw resides in the product's failure to properly validate and sanitize user-supplied archive file names, particularly those contained within .tar files that are processed by the appliance's security mechanisms.
The technical exploitation of this vulnerability leverages Perl's qx operator, a feature that executes shell commands and returns their output. Attackers can craft malicious .tar file names that, when processed by the vulnerable appliance, trigger unintended command execution through this Perl mechanism. The incomplete input validation specifically targets the file name components within the archive, allowing attackers to inject command sequences that bypass normal security controls. This type of vulnerability falls under CWE-77 and CWE-94 categories, representing command injection and code injection respectively, with the attack vector specifically targeting untrusted input processing in archive extraction routines. The attack model aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries leverage system command execution capabilities to gain unauthorized access and control.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows remote attackers to execute commands with the same privileges as the Email Security Gateway service account. This elevated access level provides attackers with substantial control over the appliance's functionality, potentially enabling them to modify security policies, access email content, redirect traffic, or establish persistent access points within the network. The appliance's role as an email security gateway makes this vulnerability particularly dangerous, as it could allow attackers to bypass email filtering mechanisms, exfiltrate sensitive communications, or disrupt email services entirely. The vulnerability affects only the appliance form factor, indicating that the web-based or cloud versions of the product may not be impacted by this specific flaw, though other attack vectors could still exist.
Security mitigations for this vulnerability were implemented through the BNSF-36456 patch, which was automatically deployed to all customer appliances. This patch addresses the root cause by implementing comprehensive input validation and sanitization for .tar file name processing, ensuring that file names are properly validated before any system command execution occurs. The automatic patch deployment mechanism demonstrates the severity of the vulnerability and the vendor's recognition of the immediate threat posed to customer deployments. Organizations should verify that the patch has been successfully applied and monitor for any unusual system activity that might indicate exploitation attempts. Additionally, network segmentation and monitoring of archive processing activities can provide additional layers of defense against potential exploitation attempts, while maintaining compliance with security standards such as those outlined in the NIST Cybersecurity Framework and ISO 27001 requirements for secure system administration and input validation.