CVE-2015-9057 in Mail Gateway
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Proxmox Mail Gateway prior to hotfix 4.0-8-097d26a9 allow remote attackers to inject arbitrary web script or HTML via multiple parameters, related to /users/index.htm, /quarantine/spam/manage.htm, /quarantine/spam/whitelist.htm, /queues/mail/index/, /system/ssh.htm, /queues/mail/?domain=, and /quarantine/virus/manage.htm.
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Analysis
by VulDB Data Team • 09/23/2020
The CVE-2015-9057 vulnerability represents a critical cross-site scripting flaw in Proxmox Mail Gateway versions prior to hotfix 4.0-8-097d26a9, exposing multiple attack vectors through various web interface components. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically manifesting as reflected XSS attacks that allow remote attackers to inject malicious scripts into web applications. The affected interfaces include user management pages, quarantine management sections, mail queue displays, and system configuration panels, creating a wide attack surface that could compromise user sessions and system integrity. The vulnerability stems from insufficient input validation and output encoding mechanisms within the Proxmox Mail Gateway's web administration interface, where user-supplied parameters are directly incorporated into dynamically generated web content without proper sanitization.
The technical exploitation of this vulnerability occurs through multiple entry points within the web application's user interface, each representing a distinct vector for XSS injection. Attackers can manipulate parameters in URLs such as /users/index.htm, /quarantine/spam/manage.htm, and /quarantine/virus/manage.htm to inject malicious JavaScript code that executes in the context of authenticated users' browsers. The attack vectors extend to /queues/mail/index/ and /system/ssh.htm, where the gateway's administrative interface fails to properly encode user input before rendering it in HTML output. When legitimate users navigate to these maliciously crafted URLs, their browsers execute the injected scripts, potentially leading to session hijacking, credential theft, or unauthorized administrative actions. The vulnerability is particularly concerning as it affects both regular users and administrators who access the mail gateway's web interface, creating a potential escalation path from low-privilege users to full administrative control.
The operational impact of CVE-2015-9057 extends beyond simple script injection, potentially enabling attackers to establish persistent access to the mail gateway infrastructure and compromise email security controls. An attacker could leverage this vulnerability to steal user session cookies, redirect users to malicious sites, or inject phishing content that could lead to credential compromise. The vulnerability's presence in quarantine management interfaces particularly threatens the gateway's core security function, as attackers could manipulate spam and virus quarantines to bypass security measures or redirect legitimate email traffic. Additionally, the attack surface includes system configuration pages that could allow attackers to modify SSH settings or other critical system parameters, potentially leading to complete system compromise. The vulnerability's persistence across multiple interface components suggests a systemic failure in input validation and output encoding practices, indicating that similar issues may exist in other parts of the application's web interface.
Mitigation strategies for CVE-2015-9057 should prioritize immediate implementation of the vendor-provided hotfix 4.0-8-097d26a9, which addresses the specific input validation weaknesses in the affected web interface components. Organizations should implement comprehensive input validation and output encoding mechanisms across all user-supplied parameters, particularly those used in dynamic web content generation. The implementation of Content Security Policy (CSP) headers can provide additional protection against XSS attacks by restricting script execution within the web application context. Network segmentation and access controls should be enhanced to limit direct web access to the mail gateway, reducing the attack surface for remote exploitation. Regular security assessments and penetration testing of web interfaces should be conducted to identify similar vulnerabilities in other components, with particular attention to the ATT&CK framework's T1059.007 technique for script injection and T1566 for phishing attacks that could exploit these vulnerabilities. System administrators should also implement monitoring solutions to detect anomalous user behavior or unauthorized access attempts that might indicate exploitation of this vulnerability, ensuring that security controls are maintained at the highest level of protection against persistent threats.