Security researchers uncovered a wireless vulnerability affecting ASUS routers that poses the risk of total network disruption.

According to Black Duck’s Cybersecurity Research Center, attackers are able to disrupt the 5 GHz Wi-Fi network via an unauthenticated Wi-Fi frame, irrespective of the network’s configured security settings. The attack can repeatedly exploited to keep the network offline until the router is manually rebooted.

“The immediate effect is the loss of connection for all clients on the 5 GHz network, preventing reconnection until the router is manually restarted. This includes guest networks as well. Ethernet connections and the 2.4 GHz network remain unaffected. After the restart, the attacker can immediately repeat the attack,” wrote Kari Hulkko, a senior software engineer at Black Duck.

The research was conducted using an ASUS RT-BE86U wireless router through fuzz testing (fuzzing), where malformed data is fed to a device to see if it crashes or behaves unexpectedly. The flaw was discovered to allow bypassing of WPA2 and WPA3 security protections, affecting firmware versions 3.0.0.6.102_37812 and older.

Black Duck traced the issue to Broadcom chipset software following collaboration with the ASUS Product Security Incident Response Team (PSIRT). The chip giant provided a software patch to address the reported problem, with Broadcom's own PSIRT team involved in the resolution process. ASUS meanwhile has released updated firmware for affected devices.

“Other devices using the same wireless chipset and/or associated software may be similarly affected, but this report is based solely on the observed test results,” added Hulkko, while revealing specific details of the vulnerability have not been disclosed by Black Duck due to its potential risk.

“Revealing such information could lead to widespread exploitation, causing significant harm to network infrastructure and compromising the security and functionality of affected devices,” said the engineer.

The exploit was graded with a High CVE score of 8.4 by Black Duck.