Tenable Discloses Verizon Fios Router Vulnerabilities

Verizon is now in the process of updating millions of routers to help protect users against a series of vulnerabilities that could have potentially enabled exploitation.

Tenable Verizon

Millions of homes across America have Verizon's Fios Quantum Gateway router as their primary conduit to the internet, and many of them could be at risk, according to new research from security firm Tenable.

On April 9, Tenable publicly disclosed that it was able to find multiple vulnerabilities in the Verizon Fios Quantum Gateway (G1000) router. The impact of the flaws is that a remote attacker could potentially get unauthorized access to the router and, by extension, the user's entire network. Tenable responsibly disclosed the vulnerabilities to Verizon in December 2018 and waited until Verizon released a firmware update fixing the issues before issuing the public disclosure.

"There are three separate flaws," Chris Lyne, senior research engineer at Tenable, told eWEEK. "However, the most impactful flaw is the authenticated command injection (CVE-2019-3914). This is remotely exploitable."

The Verizon Fios Quantum Gateway was developed by Verizon and Greenwave Systems, and it is the default router that Verizon provides to its Fios customers. Lyne first notified Verizon about the issues on Dec. 11, 2018, and received a reply from the Verizon Incident Response Team a day later. He noted that the 02.02.00.13 firmware update fixes the issues, and Verizon is in the process of auto-updating all affected devices. 

Vulnerabilities

Tenable has multiple tools in its product portfolio and is perhaps best known for being the inventor of the Nessus vulnerability scanner. Lyne stated, however, that Nessus was not used to find the Verizon gateway router bugs. Rather, he found them as part of his day-to-day research activities.

Lyne explained that the authenticated command injection attack (CVE-2019-3914) is possible in a LAN environment and when Remote Administration is enabled, the attack becomes possible remotely. He noted that there are two viable attack scenarios for this vulnerability. The first is an insider/house guest who connects to WiFi and figures out the router's public IP address. From there, they can log into the router's admin web interface to enable Remote Administration. After the house guest leaves, he or she can exploit CVE-2019-3914 remotely, from across the internet, to gain remote root shell access to the router's underlying operating system. 

The other scenario outlined by Lyne is an attacker masquerading as a Verizon tech support employee. In this situation, the attacker calls an unsuspecting Verizon customer and pretends there is an issue with their service. The attacker then asks the customer for his/her administrator password to log into the router's admin web interface and to enable Remote Administration. At this point, the attacker could ask for the public IP address, which is conveniently displayed after logging in. The attacker can then gain remote root shell access to the router’s underlying OS. 

Another flaw identified by Tenable is CVE-2019-3915, which is a Login Replay vulnerability.

"Because HTTPS is not enforced in the web administration interface, an attacker on the local network segment can intercept login requests using a packet sniffer," Tenable warned in its advisory. "These requests can be replayed to give the attacker admin access to the web interface. From here, the attacker could exploit CVE-2019-3914."

Adding further insult to injury is the CVE-2019-3916 Password Salt Disclosure vulnerability in the Verizon Gateway that Tenable also identified. A "password salt" is an additional layer of cryptographic protection that is intended to help keep secrets safe.

"An unauthenticated attacker is able to retrieve the value of the password salt by simply visiting a URL in a web browser," Tenable warned. 

What Users Should Do

Verizon is in the process of automatically updating the firmware used on the Fios Quantum Gateway. Lyne commented that Verizon customers can check their router's firmware version in a matter of minutes. First, they must log into their router's web interface. The user is "admin," and the default password is printed on the side of their router. Unless the password has been manually changed, that should log them in. After logging in, they should click System Monitoring. The firmware version will be displayed. As of now, 02.02.00.13 is the latest version, and it contains the patch.

Additionally, Lyne recommends that users should be sure that remote administration is disabled on their router. He also suggests that users change the router's administrator password so it is different from the one on the side of the router.

"We're increasingly seeing routers targeted in a variety of attacks because many are not updated frequently, if ever," Lyne said.

Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.