Hacker Finds Bug to Edit or Delete Any Medium Post (vice.com) 39
Joseph Cox, reporting for Motherboard: Medium has become the go-to home for extended blog posts from researchers, CEOs, and even the President of the United States. Now, one hacker has found a way to edit or delete any post on the publishing platform. "I tried to think of different possibilities or testing cases on how can I delete a story of any user. And fortunately, I found a severe bug," Philippines-based freelance penetration test and bug bounty hunter Allan Jay Dumanhug told Motherboard in an email. The trick, Dumanhug explained in a blog post published at the end of last month, centres around Medium's "Publications" feature. Users can create their own publications -- perhaps a page dedicated to infosec news, for example -- and then request to add other users' posts to it. Each post on Medium is given its own unique, 12-character identifier code. The person who authored the post has to approve that request, otherwise their story doesn't go anywhere. But Dumanhug found that while adding his own story to his own publication, he could intercept the HTTP request and simply change the identifier to that of another post.
And nothing of value was lost (Score:2, Insightful)
First clue was the puffery in the lede.
Where they got their name from (Score:5, Funny)
clearly the name Medium refers to their level of security.
That was almost scary (Score:3)
Astroturf much? (Score:1)
Ta-da! Now people know that Medium exists.
This sounds like story about the guy who rm -rf'd his whole webfarm.
Re:Astroturf much? (Score:4, Insightful)
Re: (Score:3)
high tech (Score:1)
I hear they are high tech. They even have Unicode support.
When will Medium go to hell? (Score:2)
Re:When will Medium go to hell? (Score:4, Informative)
So far I've been fairly pleased with reading things on Medium, although some of the weird sliding underlay pics I can do without. So when will the nice experience give way to a horrible one? When they force ads on those who run ad blockers? When they decide they aren't making enough money from the site as is? Micro transactions? So far it's been almost too good to be true.... which makes me deeply suspicious.
It's a different model. They make money using native advertising.
See, this is why we hate black-hat hackers. (Score:5, Funny)
If a white-hat hacker had found this exploit, he would've gone ahead and deleted all Medium posts. And there would have been much rejoicing.
Not very psychic (Score:2, Funny)
Any real mediums would see the deletion coming....
That's not a bug (Score:4, Informative)
That's not a bug. It's just a total lack of authentication. No put in the effort, because no one cared. Congrats. This ain't a surprise.
Perhaps a blogging platform needn't the same level of security as a bank or nuclear power centre.
A lesson for young programmers: if you're going to divulge your UIDs (or make them easily guessable, like sequential), be sure to pair them with a random string before you accept them from an outside source -- like user input.
Re: (Score:2)
Re: (Score:2)
"In this case, they fail to check whether the client is actually the owner of the post."
That would be authentication. Making sure someone is who they say they are is authentication, granting access after authentication is authorization.
Re: (Score:2)
Next level! (Score:5, Funny)
"he could intercept the HTTP request and simply change the identifier to that of another post."
Stand back guys, we got a pro here.
That explains it (Score:1)
Medium has become the go-to home for extended blog posts from researchers, CEOs, and even the President of the United States.
That explains why I haven't found a single thing on that site worth reading. I guess it's not cold enough outside to enjoy that much hot air.
Re: (Score:2)
A lot of porn sites could be gamed this way to. You get the preview and alter the URL and next thing you know your in the directory for all of that model's pics. From there it was just a matter of paying attention and recognizing some patterns and you could easily get into others.
Now granted this may appear different because you could perform "actions" but it is the same or similar because you were using the preview authentication to browse the entire paywalled contents. They wised up and eventually put an
Had to be said... (Score:5, Funny)
It's a rare Medium that's done well.
Rules for Web Developers (Score:3)
Rule 1. Never trust any user input.
Rule 2. Using encrypted checksums and other input checking to verify the contents of system generated forms before accepting them is a good thing.
StartsWithABang? (Score:2)
I expect the hacker was a disgruntled Slashdot reader who had to put up with one too many StartsWithABang posts. I'm awaiting news that Forbes is has been hacked next.