Millions Of Networked Devices In Harm's Way

Between 40 and 50 million networked devices are wide open to attack over the Internet via flaws in the pervasive Universal Plug and Play (UPnP) protocol that's enabled by default in most printers, routers, network-attached storage, IP cameras, media players, smart TVs, and even video game consoles.

A report published today by Rapid7 and spearheaded by its chief security officer HD Moore -- who for some time now under the Critical.io project has been scanning for vulnerable devices facing the Internet -- reveals several newly discovered vulnerabilities in UPnP that could be abused by attackers to remotely hack into enterprise or consumer networks via UPnP-enabled devices like printers and routers.

Some 81 million different IP addresses responded to Rapid7's UPnP discovery requests over the Internet, 40- to 50 million of which are vulnerable to at least one of three types of attacks the firm has identified, and more than 6,900 different products from 1,500 vendors. Among the brands of products Rapid7 found it its scans were Cisco Systems, D-Link, HP, NetGear, and Siemens. UPnP is basically a protocol for discovering and controlling network devices, and also is used in Microsoft Windows "Add Device" wizard, for example.

Rapid7 is warning organizations and consumers to disable UPnP immediately, or only run products that don't use UPnP. The vulnerabilities Rapid7 found in one of the most popular UPnP software library programs used in various devices -- Portable UPnP SDK -- were patched today with release 1.6.18, and the bugs it found in MiniUPnP software had actually been fixed more than two years ago: even so, some 330 vendors still run older versions of that software, according to Rapid7's findings.

All it would take is a single UDP packet to exploit devices that use Portable UPnP SDK, according to Moore, and Rapid7 found more than 23 million IPs vulnerable to this.

But disabling UPnP isn't so simple, nor is getting all of the device vendors on board to do the necessary fixes. "Most organizations don't realize they even use UPnP, and disabling it can be tricky -- not all devices support this," Moore says.

The researchers found three types of flaws: programming bugs in common UPnP discovery protocol (SSDP) implementations that can be used by an attacker to crash the service and run malicious code; the UPnP control interface, Simple Object Access Protocol (SOAP), exposes private networks to attacks on the outside Internet and can leak sensitive data; and programming flaws in the UPnP HTTP and SOAP implementations, which can also be used to crash the service and run malicious code.

Rapid7's Moore says some 17 million devices actually exposed the UPnP SOAP service. "The tricky part was figuring out what actual products were affected, what we finally found was that enough of these devices were misconfigured to expose SOAP to the world that we could use the SOAP XML page to do device fingerprinting, and from there start the notification process with CERT/CC," he says.

US-CERT has issued an advisory on the UPnP vulnerabilities and also recommended disabling UpnP if possible. Cisco was one of the first vendors to issue its own advisory, that says it's currently "evaluating" its products for exposure to the bugs. Cisco did confirm that most of its enterprise products are immune because they don't use UPnP: products running IOS, IOS-XE, IOS-XR, and NX-OS are not vulnerable, nor are its ASA Series Adaptive Security Appliance and the Firewall Services Modules.

[UPDATE]:Cisco's Linksys group, meanwhile, confirmed that several of its products are affected by the UPnP flaws, including the E900, E1200 v2, E1000 v2.1, E1500, M10 v2, WRT610N v1, and WRT610N v2. "We recommend Linksys customers visit our website to understand if their home router is affected, and learn how to disable UPnP through the user interface to avoid being impacted," Linksys said in a statement.

For Internal Use Only
UPnP was not meant for external Internet use: vendors have provided poor implementations of the protocol that put these millions of devices at risk, security experts say. And mostly at direct risk are smaller organizations and consumers, security experts say.

"What you're seeing here is attackers can hijack network connections and gain a foothold into, generally, home networks, and possibly some small businesses as well," says security researcher Dan Kaminsky. "Enterprise hardware doesn't typically use UPnP. It's a legitimate and necessary service for allowing devices to interact with their local network configurations ... It's only designed for inside the network. It just happened that in all of these devices [found by Rapid7, it's] unnecessarily exposing them to the outside world."

"Quite literally, some 50 million devices are exposed to a service that was designed only for internal [network] use," Kaminsky says.

A typical home network has one or two UPnP devices, and typical "geek" has three to four in his or her home network, Moore says. "Most companies will have between three to five per corporate network. Most office printers, network scanners, and media servers, support this," for example, he says.

What's scary is that many organizations and consumers will likely be stuck with UPnP still enabled on their devices, even with the US-CERT alert out today announcing the bugs, and the new software release and alerts from vendors. "It is a convoluted path to fix these things, and pretty unlikely that the vendors can substantially improve the situation," Moore says. "Most vendors only support the most recent devices they sell, in some cases, they have a huge number of products."

Linksys products, for example, use three- to four different UPnP implementations, depending on the model or version of the device, he says. "If the device is no longer supported by the vendor, the user is out of luck, besides turning off UPnP or replacing it," he says. "To make things worse, it seems some ISPs provide UPnP-enabled routers to their customers, and they are expensive to fix."

Many smaller vendors won't likely bother fixing the flaws, or their customers won't know there's a security update available, says Thomas Kristensen, CSO of Secunia. "And most users who aren't very knowledgeable about managing such devices will probably bail out and leave the device," he says.

The good news, however, is that there have been few widespread attacks via UPnP to date, he says. "But a higher level of visibility [about the threat now] may change that," Moore warns.

Next Page: Free Scanning Tool For UPnP

Rapid7 took data from scans it performed between June and November of last year, sending UPnP discovery requests to each and every routable IPv4 address about once a week. They found that 17 million of the UPnP devices that responded also exposed the so-called UPnP Simple Object Access Protocol (SOAP) service to the Net, which

The vulnerability management firm also released a free tool today that lets users scan for exposed UPnP devices and for those that are vulnerable to the attacks identified by Rapid7. The ScanNow UPnP tool is availablehere for download.

[Researchers and attackers catalog vulnerable systems connected to the Internet, from videoconferencing systems set to auto-answer, to open point-of-sale servers, to poorly configured database systems. See Global Scans Reveal Internet's Insecurities In 2012.]

"UPnP was intended for home use only, so hopefully most organizations won't have too many devices which support UPnP out of the box. Running a scan to be certain would be a wise move, though," Secunia's Kristensen says.

What's most disturbing, he says, is that UPnP should not be Internet-facing at all. "The risk would have been very limited if only the vendors had applied basic best practices and ensured that UPnP and similar protocols only are available in internal networks," he says.

Rapid7's Security Flaws in the Universal Plug and Play white paper is available here for download.

Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.