Remote Stack-Based Buffer Overflow in Linksys E1700

A critical stack-based buffer overflow vulnerability has been identified in the Linksys E1700 router, specifically within firmware version 1.0.0.4.003. The vulnerability resides in the ssid1MACFilter function located within the /goform/ssid1MACFilter endpoint of the Mac Filter component. By submitting a specially crafted argument to the 'newap_text_%d' parameter, an attacker can trigger an overflow on the stack. Because this endpoint is accessible over the network, the attack can be initiated remotely without authentication. The vulnerability has been publicly disclosed, and given the vendor's lack of response, there is an increased risk of active exploitation. Organizations utilizing this hardware should consider it compromised if exposed to untrusted networks.

Impact

Successful exploitation of this vulnerability leads to a stack-based buffer overflow, which can result in arbitrary code execution or permanent denial-of-service (device crash/brick) of the router. Given the device's role as a network gateway, this could allow an attacker to gain full control over the perimeter, facilitating further lateral movement or traffic interception. There is currently no vendor-provided patch.

Recommendation

• Immediately restrict access to the web management interface of all Linksys E1700 devices to trusted, internal-only management networks.
• Disable the Mac Filter functionality if it is not strictly required for network operations until a security update is released.
• Monitor perimeter logs for unexpected HTTP POST requests directed toward the /goform/ssid1MACFilter URI.
• Replace or isolate vulnerable Linksys E1700 hardware from internet-facing deployments.