CVE-2018-17989 in DSL-3782
Summary
by MITRE
A stored XSS vulnerability exists in the web interface on D-Link DSL-3782 devices with firmware 1.01 that allows authenticated attackers to inject a JavaScript or HTML payload inside the ACL page. The injected payload would be executed in a user's browser when "/cgi-bin/New_GUI/Acl.asp" is requested.
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Analysis
by VulDB Data Team • 08/21/2023
This vulnerability represents a critical stored cross-site scripting flaw in D-Link DSL-3782 routers running firmware version 1.01, classified under CWE-79 as improper neutralization of input during web page generation. The issue manifests within the device's web management interface where authenticated users can inject malicious JavaScript or HTML code through the Access Control List (ACL) configuration page. The vulnerability specifically affects the "/cgi-bin/New_GUI/Acl.asp" endpoint which fails to properly sanitize user input before rendering it back to the browser, creating a persistent XSS attack vector that can affect any user who accesses this particular page.
The technical exploitation of this vulnerability requires an authenticated attacker with administrative privileges to the device's web interface, which aligns with ATT&CK technique T1078.1.001 for valid accounts and T1547.001 for registry run keys or startup folder. Once an attacker successfully injects malicious code into the ACL page, the payload executes in the context of any user's browser session that navigates to the affected endpoint, potentially enabling session hijacking, credential theft, or redirection to malicious sites. The stored nature of this vulnerability means the malicious code persists on the device and executes every time the vulnerable page is accessed, making it particularly dangerous for network administrators who may unknowingly trigger the payload.
The operational impact of this vulnerability extends beyond simple script execution, as it can be leveraged to establish persistent backdoors within the network infrastructure. Attackers could inject code that redirects users to phishing sites, steals administrative credentials, or establishes command and control channels that bypass traditional network security measures. The vulnerability affects the core network management functionality of the DSL-3782 device, potentially compromising the entire network if administrators rely on the device's web interface for routine management tasks. Organizations using this specific router model and firmware version face significant risk of lateral movement within their networks, as the compromised device could serve as a pivot point for attacking other network resources.
Mitigation strategies should focus on immediate firmware updates from D-Link to address the identified XSS vulnerability, while network administrators should implement strict access controls limiting administrative privileges to only essential personnel. The principle of least privilege should be enforced through network segmentation and monitoring of administrative sessions to detect anomalous behavior. Additional protective measures include implementing web application firewalls that can detect and block XSS payloads, conducting regular security audits of network management interfaces, and establishing network monitoring to detect unauthorized access attempts. Organizations should also consider implementing multi-factor authentication for administrative access and regular penetration testing to identify similar vulnerabilities in other network infrastructure devices. The vulnerability highlights the importance of secure coding practices in embedded web interfaces and demonstrates how seemingly minor input validation flaws can create significant security risks in network infrastructure devices.