Huge Survey of Firmware Finds No Security Gains In 15 Years

A survey of more than 6,000 firmware images spanning more than a decade finds no improvement in firmware security and lax security standards for the software running connected devices by Linksys, Netgear and other major vendors. The Security Ledger reports: “Nobody is trying,” said Sarah Zatko, the Chief Scientist at the Cyber Independent Testing Lab (CITL), a non-profit organization that conducts independent tests of software security. “We found no consistency in a vendor or product line doing better or showing improvement. There was no evidence that anybody is making a concerted effort to address the safety hygiene of their products,” she said. The CITL study surveyed firmware from 18 vendors including ASUS, D-link, Linksys, NETGEAR, Ubiquiti and others. In all, more than 6,000 firmware versions were analyzed, totaling close to 3 million binaries created from 2003 to 2018. It is the first longitudinal study of IoT software safety, according to Zatko. CITL researchers studied publicly available firmware images and evaluated them for the presence of standard security features such as the use of non-executable stacks, Address Space Layout Randomization (ASLR) and stack guards, which prevent buffer overflow attacks.

The results were not encouraging. Time and again, firmware from commonly used manufacturers failed to implement basic security features even when researchers studied the most recent versions of the firmware. For example: firmware for the ASUS RT-AC55U wifi router did not employ ASLR or stack guards to protect against buffer overflow attacks. Nor did it employ a non-executable stack to protect against “stack smashing,” another variety of overflow attack. CITL found the same was true of firmware for Ubiquiti’s UAP AC PRO wireless access points, as well as DLink’s DWL-6600 access point. Router firmware by vendors like Linksys and NETGEAR performed only slightly better on CITL’s assessment.

CITL researchers also “found no clear progress in any protection category over time,” reports The Security Ledger. “Researchers documented 299 positive changes in firmware security scores over the 15 years covered by the study… but 370 negative changes over the same period. Looking across its entire data set, in fact, firmware security actually appeared to get worse over time, not better.”

On the bright side, the survey found that almost all recent router firmware by Linksys and NETGEAR boasted non-executable stacks. “However, those same firmware binaries did not employ other common security features like ASLR or stack guards, or did so only rarely,” says the report.