CVE-2018-20503 in 8100L-8
Summary
by MITRE
Allied Telesis 8100L/8 devices allow XSS via the edit-ipv4_interface.php vlanid or subnet_mask parameter.
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Analysis
by VulDB Data Team • 07/10/2024
The vulnerability identified as CVE-2018-20503 affects Allied Telesis 8100L and 8 series network devices, representing a cross-site scripting flaw that could enable attackers to execute malicious scripts within the context of a victim's browser session. This security weakness resides in the web-based management interface of these network appliances, specifically within the edit-ipv4_interface.php script that handles IPv4 interface configuration parameters. The vulnerability manifests when the application fails to properly sanitize user-supplied input passed through the vlanid or subnet_mask parameters, creating an avenue for malicious code injection that can be executed by unsuspecting users who interact with the affected web interface.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding mechanisms within the device's web management portal. When administrators or users submit configuration data through the web interface, the application processes the vlanid and subnet_mask parameters without sufficient sanitization measures. This allows malicious actors to inject malicious JavaScript code or other harmful payloads that persist within the application's response. The flaw operates under CWE-79 which classifies cross-site scripting as a critical weakness in web applications, where the application fails to properly validate or escape user-controllable data before incorporating it into dynamic web content.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities within the network device's management interface. An attacker could potentially steal session cookies, redirect users to malicious websites, modify network configurations, or even escalate privileges within the device's administrative interface. The vulnerability particularly affects network administrators who regularly access the device's web management console, as they become potential targets for social engineering attacks where they might unknowingly execute malicious code simply by viewing a compromised page or interacting with a maliciously crafted configuration form. This weakness creates a persistent threat vector that could compromise the integrity and confidentiality of network management operations.
Mitigation strategies for CVE-2018-20503 should prioritize immediate firmware updates from Allied Telesis to address the identified cross-site scripting vulnerability. Network administrators should implement strict input validation measures and ensure that all user-supplied data undergoes proper sanitization before being processed or displayed within the web interface. The implementation of Content Security Policy headers can provide additional protection against malicious script execution even if other security controls fail. Organizations should also consider network segmentation and access controls to limit exposure to the affected devices, while conducting regular security assessments of network infrastructure components. The vulnerability aligns with ATT&CK technique T1059.007 which involves the execution of scripts through web interfaces, and organizations should monitor for suspicious web-based activities that might indicate exploitation attempts. Regular security awareness training for network administrators can help prevent successful social engineering attacks that leverage such cross-site scripting vulnerabilities.