Silent Circle patches Blackphone vulnerability

A report released this morning shows that no phone is 100 percent secure — but that one company, at least, is able to respond quickly and issue patches immediately.

An open socket on the Blackphone made its nVidia modem accessible to apps without those apps having to first get user permissions. When combined with other vulnerabilities, such as those allowing execution of remote code, this could potentially allow websites to secretly use a phone to make phone calls or send text messages.

The company that makes the phone, Silent Circle subsidiary SGP Technologies, has already fixed the problem, said Tim Strazzere, director of mobile research at SentinelOne, which issued the report.

Strazzere said that the speed at which the company responded was impressive. In the past, he’s found other vulnerabilities and is still waiting for the vendors to issue updates.

Blackphone is marketed as the most secure smartphone available, and the company promises fast updates — and they delivered, Strazzere said.

“When I reached out to them, they responded immediately,” he said. “They were very interested in what I found, and asked for my suggestions, fixed the problem, asked me to check it, and then pushed the update as fast as possible,” he said.

All the Blackphone devices should now be fixed, he said.

The modem at the heart of the vulnerability, the Icera modem which used to be made by nVidia but is no longer on the market, is used by a couple of other tablets and phones, Strazzere said, but they were only available in India and are also no longer on the market.

“I wasn’t able to acquire any of them,” he said.

The vulnerability allowed apps to secretly send and receive text messages, make phone calls, set call forwarding and perform other potentially dangerous functions — all without requesting any permissions from the user when the app is installed.

That means that a user could be installing what looks to be a completely safe and secure flashlight app, which requires no permissions, but may actually be installing harmful spyware.

That’s risky enough all by itself, but can be even more dangerous if combined with other vulnerabilities.

“You could leverage this to do even more interesting things,” said Strazzere.

SentinelOne first discovered the vulnerability in late August and contacted Silent Circle, then submitted the issue, as requested, via BugCrowd in September. Silent Circle acknowledged the submission the same month, and resolved the issue and created a patch in four weeks. The patch was distributed in early December.

BugCrowd is a bug bounty platform used by companies such as Western Union, Pinterest and Aruba Networks.

Silent Circle’s BugCrowd bug bounty program specifically prohibits researchers from releasing information about vulnerabilities to the public before they are resolved.