PoC exploit launched for RCE zero-day in D-Hyperlink EXO AX4800 routers

The D-Hyperlink EXO AX4800 (DIR-X4860) router is weak to distant unauthenticated command execution that would result in full machine takeovers by attackers with entry to the HNAP port.

The D-Hyperlink DIR-X4860 router is a high-performance Wi-Fi 6 router able to speeds of as much as 4800 Mbps and superior options like OFDMA, MU-MIMO, and BSS Coloring that improve effectivity and scale back interference.

The machine is notably common in Canada, and it is bought within the international market in accordance with D-Hyperlink’s web site, and nonetheless actively supported by the seller.

Immediately, the SSD Safe Disclosure staff of researchers introduced that they found flaws in DIR-X4860 gadgets working the most recent firmware model, DIRX4860A1_FWV1.04B03, which permits unauthenticated distant command execution (RCE).

“Security vulnerabilities in DIR-X4860 allow remote unauthenticated attackers that can access the HNAP port to gain elevated privileges and run commands as root,” reads SSD’s disclosure.

“By combining an authentication bypass with command execution the device can be completely compromised.”

Accessing the House Community Administration Protocol (HNAP) port on the D-Hyperlink DIR-X4860 router is comparatively easy most often, because it’s normally HTTP (port 80) or HTTPS (port 443) accessible via the router’s distant administration interface.

Exploitation course of

The SSD analysts have shared step-by-step exploitation directions for the problems they found, making a proof-of-concept (PoC) exploit now publicly out there.

The assault begins with a specifically crafted HNAP login request to the router’s administration interface, which features a parameter named ‘PrivateLogin’ set to “Username” and a username of “Admin”.

The router responds with a problem, a cookie, and a public key, and these values are used to generate a sound login password for the “Admin” account.

A follow-up login request with the HNAP_AUTH header and the generated LoginPassword is shipped to the goal machine, primarily bypassing authentication.

Login request that bypasses the authentication step
Login request that bypasses the authentication step
Supply: SSD Safe Disclosure

With authenticated entry, the attacker then exploits a command injection vulnerability within the ‘SetVirtualServerSettings’ operate by way of a specifically crafted request.

The weak ‘SetVirtualServerSettings’ operate processes the ‘LocalIPAddress’ parameter with out correct sanitization, permitting the injected command to execute within the context of the router’s working system.

SSD says it has contacted D-Hyperlink 3 times to share its findings with the router maker over the previous 30 days, however all makes an attempt to inform them have been unsuccessful, leaving the failings at the moment unfixed.

BleepingComputer has additionally reached out to D-Hyperlink with a associated request, and we’re nonetheless ready for a remark.

Till a safety firmware replace is made out there, customers of the DIR-X4860 ought to disable the machine’s distant entry administration interface to stop exploitation.

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