While the company was blasted for its opaque relationship with China's government in a U.S. intelligence report released Monday, a bigger worry for some is what's inside its routers.
"The code quality is pretty much from the '90s," said Lindner, who has analyzed the software inside Huawei's home and enterprise routers, and runs , a security consultancy, in Berlin.
Lindner will speak on Thursday at the Hack in the Box security conference in Kuala Lumpur and discuss some of the vulnerabilities he and a fellow researcher disclosed earlier this year along with an overview of Huawei's security.
When Lindner began looking at Huawei's routers, the company didn't have a prominent product security team, Lindner said. But since he and colleague Gregor Kopf in the firmware of Huawei's AR18 series routers, which are meant for homes, and its AR29 series routers, intended for small enterprises, at the Defcon conference in July, "they seem to be trying to ramp up product security in a visible way right now," he said.
Lindner's conclusion comes as Huawei is a blistering report released this week by the U.S. House of Representatives' Permanent Select Committee on Intelligence. The report alleges that Huawei and another Chinese company, ZTE, pose a threat to U.S. infrastructure and postulates their equipment could be secretly modified by Chinese intelligence agencies.
The accusations contained in the report are broad and unspecific. Lindner said the report is "lacking truth in data," which is exactly why he tears apart millions of lines of router code looking for security problems. With Huawei, he's found plenty.
"I'm somewhat in support of what the report says, not for the reasons the report says but simply because of quality assurance," Lindner said. "I'd rather have Cisco build government networks than Huawei, not because Huawei is Chinese, but because in comparison, Cisco has higher-quality devices."
After the vulnerabilities were detailed at Defcon, Huawei said it has rigorous security practices and follows industry best practices.
Still, it is possible that even a simple coding mistake could leave Huawei vulnerable to accusations of working with Chinese intelligence. Lindner said it is very difficult to figure out what is a "backdoor" in code, or a way get inside a system.
For example, if security researchers discover an engineer account that wasn't deleted before router code was finalized, it could give ammunition to critics that the company was in collusion with other interested parties.
"It's hard to argue with a root shell," Lindner said.