CVE-2015-5453 in XCS
Summary
by MITRE
Watchguard XCS 9.2 and 10.0 before build 150522 allow remote authenticated users to execute arbitrary commands via shell metacharacters the id parameter to ADMIN/mailqueue.spl.
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Analysis
by VulDB Data Team • 06/30/2024
The vulnerability identified as CVE-2015-5453 affects Watchguard XCS appliances running versions 9.2 and 10.0 before build 150522. This represents a critical command injection flaw that allows authenticated remote attackers to execute arbitrary commands on the affected systems. The vulnerability specifically resides in the ADMIN/mailqueue.spl component where the id parameter fails to properly sanitize user input, creating an avenue for malicious command execution.
This security weakness stems from inadequate input validation and sanitization practices within the web interface of the Watchguard XCS appliance. The flaw operates through a classic command injection vector where the id parameter in the mailqueue.spl script does not properly escape or filter special shell metacharacters. When an authenticated user submits malicious input containing shell metacharacters such as semicolons, ampersands, or backticks, these characters are interpreted by the underlying shell and executed as commands. This vulnerability falls under the CWE-77 category of Command Injection, which is categorized as a high-risk vulnerability in the CWE top 25 most dangerous software weaknesses.
The operational impact of this vulnerability is severe as it provides attackers with the ability to execute arbitrary commands with the privileges of the web application user, typically running with elevated system privileges. Successful exploitation could lead to complete system compromise, allowing attackers to install backdoors, exfiltrate sensitive data, modify system configurations, or establish persistent access to the network. The authenticated nature of the attack means that an attacker would need valid credentials to exploit this vulnerability, but once compromised, the impact extends beyond simple privilege escalation to full system control.
From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation. The attack chain typically involves initial access through legitimate credentials followed by exploitation of the command injection vulnerability to execute malicious payloads. Organizations should consider implementing network segmentation to limit access to administrative interfaces and deploy intrusion detection systems to monitor for suspicious command execution patterns. The vulnerability highlights the importance of proper input validation and the principle of least privilege in web application development, where all user-supplied inputs should be rigorously sanitized before processing. Remediation requires immediate patching of the affected Watchguard XCS appliances to build 150522 or later, along with comprehensive network monitoring to detect potential exploitation attempts. Organizations should also review their authentication practices and implement multi-factor authentication to reduce the risk of credential compromise that could lead to exploitation of this vulnerability.