CVE-2013-20008 in WAG200G
Summary
by MITRE • 10/28/2026
Linksys WAG200G through 1.01.06 contains a weak password change mechanism that allows attackers to change the administrator password without supplying the current password. Attackers with access to an authenticated administrator browser session can set a new password to lock out the legitimate administrator and take persistent device control.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in Linksys WAG200G firmware versions up to 1.01.06 represents a critical authentication bypass flaw within the web-based administrative interface of the router. This security defect allows an attacker who has obtained access to an authenticated administrator session, potentially through credential theft or session hijacking, to modify the device's configuration without providing proof of ownership for the current password. The core technical failure lies in the server-side validation logic which fails to verify that the user submitting the new password request is indeed the legitimate owner by requiring the entry of the existing credentials. This design oversight effectively decouples the action of changing administrative privileges from the requirement of proving prior authorization, creating a significant gap in access control mechanisms.
From an operational perspective, this flaw enables persistent device compromise and denial of service against the legitimate administrator. An attacker with even temporary or ephemeral access to the authenticated session can immediately change the password, thereby locking out the rightful owner who no longer possesses valid credentials for administrative functions. This action not only grants the attacker full control over network configuration settings but also facilitates long-term persistence by preventing remediation efforts from the original user. The ability to alter passwords without current credential verification undermines the fundamental principle of least privilege and ensures that once an initial foothold is gained, it can be solidified into permanent administrative access.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-287, which describes Improper Authentication, specifically relating to insufficient checks for authentication credentials during state-changing operations. Furthermore, the exploitation technique maps directly to MITRE ATT&CK tactic T1098, Account Manipulation, where adversaries alter accounts to maintain access or escalate privileges without detection by legitimate users. The lack of multi-factor verification or session-bound token validation for sensitive configuration changes exemplifies a failure in implementing robust identity and access management protocols within embedded web services.
Mitigation strategies must focus on immediate patching and architectural improvements. Users should update the firmware to version 1.01.07 or later where this logic error has been corrected to require current password verification before allowing administrative credential changes. In environments where updating is not immediately feasible, network segmentation can limit exposure by restricting management interfaces from untrusted networks. Additionally, implementing strict session timeout policies and monitoring for unusual configuration change events can help detect exploitation attempts early. Future development cycles must enforce rigorous input validation that ties sensitive state modifications to verified current credentials or alternative strong authentication factors to prevent unauthorized privilege escalation.