'The Kardashians' Billboard Covered Up in L.A. After NSFW Graffiti Job

The Kardashians got hit by a local graffiti tagger in L.A. -- or at least their billboard did ... which got spray painted with a pretty nasty message, which has already been obscured.

Check out this photo we obtained ... the massive advertisement -- featuring Kris, Kim, Khloe, Kourtney, Kendall and Kylie, all posing for a promo for their Hulu show "The Kardashians" -- was sitting high above Los Angeles traffic in a prominent area in town this week.

While the billboard for season 5 originally boasted the tagline, "New Horizons Await," one graffiti artist decided to send a different message ... writing, "Suck the D*** Right!"

Indeed, it's a straight vandalism job that stood out like a sore thumb -- with the giant lettering sitting right underneath the photo of the KarJenners. A TON of people noticed it Thursday.

The vulguar and NSFW graffiti tag was clearly the work of someone looking to take a high profile jab at the family -- but their smear was covered pretty quickly.

We got extra photos from later Thursday that show the vandalized billboard completely blacked out  ... as you can see, the entire signage has been covered up.

Fact is the graffiti would ruin the whole poster -- no word on if a brand new 'Kardashians' billboard will go up in its place.

"The Kardashians" season 5 is already streaming at this point ... making a splash with updates on Kim and Kourtney's feud, Scott Disick's weight loss drugs, and Rob Kardashian's ejaculation status. Every year the show airs, it dominates headlines.