The feature, called WebScan, allows a user to remotely trigger the scanning functionality and retrieve scanned images via a web browser. This capability could allow anyone on the local area network (LAN) to remotely connect to the scanner and retrieve documents that have been left behind on the scanner, Michael Sutton, vice president of security research at Zscaler, told SCMagazineUS.com on Thursday.
The feature generally is turned on by default and, in many cases, is not password protected.
“This does present a fairly significant security issue,” Sutton said.
Hypothetically, a disgruntled employee could write a script to regularly run the scanner in hopes of capturing a forgotten confidential document, he said. Or a script could be written to run frequently, allowing a malicious insider to capture any documents that have been scanned using the WebScan feature.
Also, an attacker could remotely abuse this functionality to obtain sensitive documents via scanners that have been exposed on the internet due to misconfigured networks, Sutton said.
When used as intended on a secured network, WebScan is a tool that allows consumers and small-to-midsize businesses to share information quickly and conveniently, HP said in a statement.
“HP encourages customers that use its products in a network setting to ensure that their network is properly encrypted and network security information is only provided to trusted parties,” the company said.
Zscaler researchers were able to discover numerous HP scanners that were exposed on the internet and were not password protected. As a result, the researchers were able to remotely retrieve a number of sensitive documents from the HP scanners, such as checks, legal documents, completed ballot forms, phone numbers and certificates.“I think the internal threat is actually the greater one from the enterprise perspective,” Sutton said. “The majority of organizations aren't going to be exposed externally. What's more concerning is that there are millions of these scanners in enterprises and people likely don't realize this feature exists, and anyone on that network has the ability to run that scanner.”
Most all-in-one HP Photosmart and Officejet printers sold within the last several years have some variation of the WebScan functionality, Sutton said. It is possible that printers from other manufacturers also could be affected by similar issues.
Zscaler has released a script on its blog to help users determine if they have any HP scanners on their LAN. Users can help prevent the function from being abused by setting an admin password for their device, Sutton said.
It is becoming increasingly commonplace for printers, faxes and other hardware devices to be IP enabled and connected to the general-purpose computing environment within an organization, Sutton said.
Any IP-enabled device can be exploited or used as an entry point into a network to attack other hosts on the network, Kevin Brown, delivery manager of custom testing at ICSA Labs, a security solutions tester, told SCMagazineUS.com in an email on Thursday.
Many IP-enabled devices use some sort of web server for administration and configuration that could introduce threats, Brown said. If the web server was custom built, it likely was not subjected to the same level of security testing as a more commonly available web server.
If it is based on a common web server, such as Apache or IIS, it inherits any vulnerabilities that that particular web server has, he added.
In addition, users are accustomed to patching their software for flaws, but generally never upgrade the firmware on their printer or other IP-enabled devices, Sutton said. And patching an embedded web server may not even be possible in some cases.
“Typically, if there is a security vulnerability in a piece of hardware, it's there for good,” Sutton said.
