CVE-2018-8827 in MediaAccess TG789vac v2 HP
Summary
by MITRE
The admin web interface on Technicolor MediaAccess TG789vac v2 HP devices with firmware v16.3.7190-2761005-20161004084353 displays unsanitised user input, which allows an unauthenticated malicious user to embed JavaScript into the Log viewer interface via a crafted HTTP Referer header, aka XSS.
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Analysis
by VulDB Data Team • 04/26/2020
The vulnerability identified as CVE-2018-8827 affects Technicolor MediaAccess TG789vac v2 HP devices running firmware version v16.3.7190-2761005-20161004084353 and represents a critical cross-site scripting flaw within the device's administrative web interface. This vulnerability specifically impacts the Log viewer component where user input from the HTTP Referer header is not properly sanitized before being rendered back to the browser. The flaw exists in the web application's input validation mechanisms, creating a pathway for malicious actors to inject arbitrary JavaScript code into the interface. The vulnerability is particularly concerning because it operates without requiring authentication, making it accessible to any remote attacker who can craft a malicious HTTP request.
The technical implementation of this vulnerability stems from improper output encoding and input validation practices within the web application's backend processing. When the device receives an HTTP request containing a crafted Referer header, the system fails to sanitize or escape the input before displaying it in the Log viewer interface. This creates an environment where JavaScript code can be executed within the context of the victim's browser session, potentially allowing attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or executing additional attacks through the compromised interface. The vulnerability maps directly to CWE-79 which defines Cross-Site Scripting as a weakness where untrusted data is incorporated into web pages without proper validation or escaping.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a foothold into the device's administrative interface. An attacker could leverage this vulnerability to gain unauthorized access to sensitive device information, modify device configurations, or establish persistent access points. The unauthenticated nature of the attack means that no credentials are required to exploit this flaw, significantly increasing the attack surface and potential for widespread compromise. This vulnerability aligns with ATT&CK technique T1059.007 which covers the use of JavaScript for malicious purposes, and T1071.004 which involves application layer protocol usage for command and control communications.
Mitigation strategies for CVE-2018-8827 should focus on immediate input sanitization and output encoding measures within the web application. The device firmware should be updated to properly escape all user-supplied input before rendering it in the web interface, particularly within the Log viewer component. Network segmentation and access controls should be implemented to limit exposure of administrative interfaces to trusted networks only. Regular security audits of web applications should include thorough input validation testing to identify similar vulnerabilities. Organizations should also consider implementing web application firewalls to detect and block malicious Referer headers. The vulnerability highlights the importance of following secure coding practices as outlined in OWASP Top 10 and NIST guidelines for preventing XSS attacks, emphasizing that input validation and output encoding are fundamental security controls that must be implemented at every layer of web application development.