Security vulnerabilities found in Belkin Wi-Fi routers
The CERT Software Engineering Institute has uncovered a series of vulnerabilities in the Belkin N600 DB Wireless Dual Band N+ router.
These vulnerabilities affect those with firmware version 2.10.17 and possibility those with earlier versions as well, according to CERT.
More specifically, CERT has highlighted the following vulnerabilities:
Use of insufficiently random values
DNS queries originating from the Belkin N600, such as those to resolve the names of firmware update and NTP servers, use predictable TXIDs that start at 0x0002 and increase incrementally.
An attacker with the ability to spoof DNS responses can cause the router to contact incorrect or malicious hosts under the attacker's control.
Cleartext transmission of sensitive information
Belkin uses HTTP by default for checking and transmitting firmware update information to vulnerable routers.
An attacker capable of conducting man-in-the-middle attacks can manipulate traffic to block updates or inject arbitrary files.
Belkin N600 by default does not set a password for the web management interface.
A local area network (LAN) attacker can gain privileged access to the web management interface or leverage the default absence of credentials in remote attacks such as cross-site request forgery.
Use of client-side authentication
When a password is implemented in the Belkin N600 web management interface, authorisation is enforced client-side by the browser.
By intercepting packets from the embedded server containing the strings "LockStatus": "1" and"Login_Success": "0" and modifying the values to "2" and "1" respectively, an attacker can bypass authentication and gain full, privileged access to restricted pages of the web management interface.
Cross-site request forgery (CSRF)
Belkin N600 routers contain a global cross-site request forgery (CSRF) vulnerability. An attacker can perform actions with the same permissions as a victim user, provided the victim has an active session and is induced to trigger the malicious request.
Note that in default configurations lacking password protection, an attacker can establish an active session as part of an attack and does not require a victim to be logged in, CERT says.
According to CERT, these vulnerabilities could allow a remote, unauthenticated attacker to spoof DNS responses to cause vulnerable devices to contact attacker-controlled hosts, or induce an authenticated user into making an unintentional request to the web server that will be treated as an authentic request.
Furthermore, A LAN-based attacker can bypass authentication to take complete control of vulnerable devices.
These vulnerabilities don’t have any practical solutions, says CERT, and until they have been addressed users should consider ‘workarounds’.
The advisory says, “As a general good security practice, only allow trusted hosts to connect to the LAN. Implement strong passwords for WiFi and for the web management interface.
“While passwords do not provide any additional security against LAN-based attackers due to the authentication bypass vulnerability, passwords can help to prevent blind guessing attempts that would establish sessions for CSRF attacks.
“LAN hosts should not browse the internet while the web management interface has an active session in a browser tab.”
However, as far as CERT is aware, there are no practical workarounds for the DNS spoofing or firmware over HTTP issues, as general users are unlikely to be able to monitor traffic entering the router's WAN port.