CVE-2016-1326 in DPQ3925
Summary
by MITRE
The administration interface on Cisco DPQ3925 devices with firmware r1 allows remote attackers to cause a denial of service (device restart) via a crafted HTTP request, aka Bug ID CSCup48105.
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Analysis
by VulDB Data Team • 07/10/2022
The Cisco DPQ3925 device represents a consumer-grade cable modem that incorporates an administration interface accessible through HTTP protocols. This particular vulnerability exists within the firmware version r1, where the device fails to properly validate incoming HTTP requests submitted through its web-based management portal. The flaw manifests as a lack of input sanitization and request handling mechanisms that would normally prevent malformed or malicious requests from causing system instability. Attackers can exploit this weakness by crafting specific HTTP requests that, when processed by the device's web server, trigger an unexpected behavior resulting in a complete system restart.
The technical implementation of this vulnerability stems from insufficient bounds checking and parameter validation within the device's HTTP request processing pipeline. When the administration interface receives a malformed HTTP request containing specially crafted headers or parameters, the device's embedded web server does not properly handle the malformed input and instead crashes or enters an undefined state. This condition forces the device to reboot automatically, effectively causing a denial of service condition that disrupts network connectivity for all users relying on the modem. The vulnerability operates at the application layer of the network stack and specifically targets the web server component responsible for handling administrative requests.
The operational impact of this vulnerability extends beyond simple service disruption as it can be exploited remotely without requiring authentication credentials, making it particularly dangerous for unattended devices. Network administrators may experience unexpected downtime during critical periods, while the device's automatic restart behavior can lead to repeated service interruptions if attackers continuously exploit the flaw. The vulnerability affects devices deployed in residential and small business environments where modem management interfaces are often left accessible to unauthorized users. This creates a persistent risk for network availability and can potentially be leveraged as part of larger attack campaigns targeting network infrastructure.
Mitigation strategies for this vulnerability should focus on immediate firmware updates provided by Cisco to address the specific input validation flaws in the web server component. Network administrators should ensure that all affected devices receive the latest firmware releases that include proper request validation and bounds checking mechanisms. Additionally, implementing network segmentation and access control measures can help restrict access to the administration interface to trusted network segments only. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and can be classified under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider disabling the web administration interface entirely when it is not actively needed, as this reduces the attack surface and prevents exploitation of the underlying flaw.