Login passwords for tens of thousands of Dahua digital video recorder devices have been cached by ZoomEye, an IoT search engine, and published on the web so that even the dumbest hacker could crack unpatched kit.
“A new low has been achieved in the ease of hacking IoT devices,” said Ankit Anubhav, principal researcher at NewSky Security. “One does not even need to connect to the Dahua devices to get the credentials.”
Many Dahua DVR devices can be hijacked by exploiting a five-year-old firmware-based vulnerability (CVE-2013-6117).
This specific security flaw is one of many that has been used over recent months by the author of the BrickerBot IoT malware, which bricks insecure IoT devices in an attempt to force users into applying security updates.
In short, the vulnerability can be exploited like this: connect to a Dahua DVR on TCP port 37777 over the internet, and without any authentication, you can ask it to spit back a binary blob containing the machine’s serial number, settings, and passwords. With these details, you can remotely log into the device’s web-based control panel, and spy on its owner via the recorded camera video, and cause other mischief.
ZoomEye handily indexes not just internet-facing Dahua DVRs by their public IP address, it also fires off the necessary requests to port 37777 to retrieve the devices’ passwords, and caches it for world-plus-dog to view and use. In other words, it appears to exploit the vulnerability, which is a step further than rival search engines, such as Shodan.io.
This cached information is enough to allow unskilled would-be hackers to remotely hijack and abuse vulnerable recording devices.
Making life simple for scumbags
Anubhav argued that searching for and exploiting vulnerable Dahua DVR devices has been radically simplified using ZoomEye, which is seemingly based in China. ZoomEye’s lead developer for its security team, Heige, has yet to respond directly to El Reg about whether or not it intends to obfuscate search results that could be useful to script kiddies.
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Even though the underlying vulnerability is five years old, simple search queries on ZoomEye are enough to unearth thousands of Dahua DVRs ripe for exploitation. It seems Dahua is happy to sell kit that is insecure, and not help ensure its customers are patched and safe.
The whole sorry affair shows just how easy it has become to exploit IoT devices almost two years after the Mirai IoT botnet rendered many high profile sites inaccessible in an attack some thought might spur a radical shake up. Anubhav favours regulation to impose baseline security standards.
“There should be strict regulations for devices to have an update feature, which can be used to automatically push patches to the firmware as soon as the device is connected to the internet,” Anubhav told The Register.
“As long as an IoT device has a strong password and is updated, it should take care of the bulk of the problem. Zero days will still pop up, but most IoT attackers use known passwords/exploits to hack, and they will fail in their attempts.”
El Reg invited Dahua, which is headquartered in China, to comment on whether automatically pushing security updates to vulnerable devices might be the best way out of the mess. We’re yet to hear back from the manufacturer but will update this story as and when learn more. ®
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