Lenovo NAS Firmware Flaw Exposes Stored Data

Thousands of users of Lenovo network-attached storage devices are at risk of data compromise via a firmware-level vulnerability.

The flaw, which is present in certain models of the NAS products, allows unauthenticated users to view and access data stored on the devices, and is trivially easy to exploit via the Application Programming Interface, researchers from Vertical Structure and WhiteHat Security said this week.

An initial investigation of the issue uncovered at least 5,114 of the devices exposed on the Internet with over 3 million files vulnerable to the issue. But the total number of such at-risk Lenovo storage systems could be higher.  

The researchers found that Google had already indexed several of these exposed devices, resulting in some 13,000 spreadsheet files with 36 terabytes of data available on the Web. Many of exposed files had sensitive data in them, including credit card numbers and financial records.

"The API is completely unauthenticated and provided the ability to list, access, and retrieve the files remotely in a trivial manner," says Simon Whittaker, director at Vertical Structure. "It is similar to thousands of open [AWS] S3 [storage] buckets being discovered." 

The devices impacted by the issue include several models of Iomega's StorCenter and LenovoEMC's series of NAS systems. Several of the impacted models have reached end-of-life status, so Lenovo is no longer supporting or maintaining them.

High Severity Issue

In an alert Tuesday that lists all impacted devices, Lenovo described the vulnerability as high severity because it allows unauthenticated access to files on NAS shares via the API. The company urged users of vulnerable devices to immediately update their firmware to the latest available version.

In situations where a user might not be immediately able to update the firmware for any reason, they should remove any public shares and use the device only on trusted networks, Lenovo said. By taking this measure organizations can achieve "partial protection" from the vulnerability, according to the vendor.

Whittaker says Vertical Structure uncovered the issue last fall when a routine Shodan scan unearthed a collection of unmarked files that researchers were later able to trace back to external hard drives from Iomega. After some investigating, the researchers found the external hard drives would leak information through specially crafted requests via an API, but not through their Web interface, he says.

Researchers from Vertical Structure then worked with counterparts from WhiteHat Security to confirm the vulnerability and later inform Lenovo about it.

In the devices found directly accessible from the Internet, all that an attacker would need to grab data from them is knowledge of the NAS's IP address, Whittaker says. And for devices not directly accessible from the Internet, an attacker would need to be on the same network in order to exploit the vulnerability, he says.

When Lenovo itself was first informed of the issue, the company pulled three versions of its NAS software out of retirement so users could continue to utilize their product while a fix was being readied, Vertical Structure said.

The firmware update the company has released fundamentally changed the API and the Web interface, in order to secure it, Whittaker explains.

The data in the vulnerable devices presents a treasure trove of information about people and organizations, he notes. "By putting this information online they assumed it would be secure and protected by the username and password," Whittaker says. "But this was incorrect."

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