While unconfirmed, it's heavily speculated that the maintenance - which at the time of writing has no time frame attached to it - is linked to the 'ENLBufferPwn' exploit detailed in the article below.
As a quick reminder, the exploit effectively allows attackers to gain control of target Wii U and 3DS consoles by simply connecting to players online.
Hopefully the maintenance will prevent the exploit from being used in the future, however it's currently unknown when exactly the online services for Splatoon and Mario Kart 8 will be back up and running.
Original Article [Wed 28th Dec, 2022 11:15 GMT]:
A severe vulnerability affecting several Nintendo consoles was found recently, with the potential to allow unauthorised access to Switch, 3DS, and Wii U via a host of online games. It's reported that for some time Nintendo has been working to patch games to eliminate the exploit known as 'ENLBufferPwn', with several updates already live to address the situation (thanks, Nintendo Everything).
The vulnerability, which has been categorised as 'Critical' on the Common Vulnerability Scoring System (CVSS) and detailed in full on GitHub by PabloMK7, Rambo6Glaz, and Fishguy6564, reportedly exposes a victim's device to complete remote control by simply playing an online game with a potential attacker. This means that attackers may gain access to sensitive information or take audio and video recordings by remotely executing code.
The vulnerability was reported to Nintendo in "2021/2022" by @Pablomf6 — who says they received a $1000 "bounty" via Nintendo's HackerOne program — and it is now understood that the company has taken action to fix the issue in some of the affected games, including Mario Kart 7, which was recently updated after more than a decade.
It seems most high-profile Switch titles have already been fixed, but it looks like Mario Kart 8 and Splatoon on Wii U have yet to be addressed and may still be affected by the vulnerability.
Here's a list of affected titles, as per the GitHub page:
- Mario Kart 7 (fixed in v1.2)
- Mario Kart 8
- Mario Kart 8 Deluxe (fixed in v2.1.0)
- Animal Crossing: New Horizons (fixed in v2.0.6)
- ARMS (fixed in v5.4.1)
- Splatoon 2 (fixed in v5.5.1)
- Splatoon 3 (fixed in late 2022, exact version unknown)
- Super Mario Maker 2 (fixed in v3.0.2)
- Nintendo Switch Sports (fixed in late 2022, exact version unknown)
It's speculated that other games may also be affected by the vulnerability, although that's unconfirmed at present.
For a look at the exploit in action, take a peek at the below video from PabloMK7 which demonstrates an attacker (left console) remotely taking over an unmodified 3DS (right side) by copying a return-oriented programming (ROP) payload and executing it remotely. The victim console is then forced to run a custom firmware installer and it's thought that the same technique would allow an attacker to steal sensitive information from a remote console. Thankfully, this has now been fixed and can no longer be carried out if you're running the latest version of the software, so be sure to update if you haven't!
Nintendo's relatively limited approach to online play seems to have its advantages when it comes to security issues like this, as pointed out by @LuigiBlood discussing the exploit:
Those two games mentioned are Mario Kart 8 and Splatoon, so if you still play either of those titles online on your Wii U, we recommend exercising extreme caution or avoiding them altogether until more information is available. We'll update this article if further details come to light.
What do you make of this? Share your thoughts in the comments below.