Back in May we posted about CVE-2022-27254 where university student researchers discovered that the wireless locking system on several Honda vehicles was vulnerable to simple RF replay attacks. A replay attack is when a wireless signal such as a door unlock signal is recorded, and then played back at a later time with a device like a HackRF SDR. This vulnerability only affected 2016-2020 Honda Civic vehicles which came without rolling code security.

Recently a new vulnerability discovered by @kevin2600 that affects ALL Honda vehicles currently on the market (2012-2022) has been disclosed. The vulnerability is dubbed 'Rolling-PWN' (CVE-2019-20626) and as the name suggests, details a method for defeating the rolling code security that exists on most Honda vehicles. Rolling code security is designed to prevent simple replay attacks, and is implemented on most modern vehicles with wireless keyfobs. However @kevin2600 notes the following vulnerability that has been discovered:

A rolling code system in keyless entry systems is to prevent replay attack. After each keyfob button pressed the rolling codes synchronizing counter is increased. However, the vehicle receiver will accept a sliding window of codes, to avoid accidental key pressed by design. By sending the commands in a consecutive sequence to the Honda vehicles, it will be resynchronizing the counter. Once counter resynced, commands from the previous cycle of the counter worked again. Therefore, those commands can be used later to unlock the car at will.

The vulnerability has been tested on various Honda vehicles with HackRF SDRs, and this seems to indicate that all Honda vehicles since 2012 are vulnerable.

Although no tools have been released, the vulnerability is simple enough and we've already seen people replicate results.

— Rob Stumpf (@RobDrivesCars) July 10, 2022

The story of Rolling-Pwn has already been covered by magazines and news organizations such as TheDrive, Vice, NYPost, and FoxLA.

It should be noted that when the previous replay attack vulnerability was highlighted, Honda released a statement noting that it has no plans to update its older vehicles. It is likely that Honda will not issue updates for this vulnerability either. It is possible that this vulnerability extends beyond just Honda vehicles too.